Reconstructing the Past

Methods, Evidence, Examples

Methods of Inquiry

It brings insight to divide the principal methods of inquiry into two broad, distinct categories: those that reconstruct the past and those that discover or create new knowledge. The first is the method of the historian, archeologist, epidemiologist, journalist, and criminal investigator; the second, that of the scientist in general (as well as the creative artist). Although usefully stated as a dichotomy for the sake of a conceptual distinction, these methods finally fuse in the minds of the better thinkers and practitioners, for the reconstruction of the past often makes use of the scientific method, while science and art build on and digress from the past. Further reflection suggests that any thorough inquiry employs techniques common to both. This certainly applies to the best practice in criminal investigation. Disciplines as diverse as geology, physical geography, physical anthropology, forensic medicine, statistics, computer technology, and criminalistics can make a contribution. Indeed, the discrete methods they employ may be seen as a continuum, with the ideal drawing on history, science, and art in varying proportions depending on the subject under probe. Therefore, just as the model investigation must utilize both principal methods of inquiry, so must the model investigator. This is not to say that a unique investigative technique may not be developed to deal with a specific problem, and be helpful with others as well. For testing the authenticity of a confession, for example, the tools of psycholinguistics could be put to use. That they have not been put to use thus far indicates the wide range of resources yet to be tapped by criminal investigators.

More than 30 years ago, the sociologist W.B. Sanders1 and the historian Robin Winks2 saw the relationships between their fields and the field of criminal investigation. They see the parallels between the ivory-towered inquirer and society’s more familiar figure, the detective: both study human behavior and both employ information-gathering practices such as interviews and observations. Sanders recognizes that the sociologist can learn from the detective, among other things, how to combine several methods of inquiry (or research) and sources of information (or data) into a single inquiry. Winks’s selection of essays by writers and historians reveals how scholars penetrate rumors, forgeries, false accounts, and misleading clues to unravel old mysteries. Not only do the essays “point up the elements of evidence within them to emphasize leads and clues, straight tips, false rumors, and the mischief wrought by time,” they demonstrate that the historian and detective are on common ground when confronting the techniques and pitfalls of dealing with evidence.3

The historian must collect, interpret, and then explain his evidence by methods which are not greatly different from those techniques employed by the detective, or at least the detective of fiction. … Perhaps the real detective trusts more to luck, or to gadgetry, or to informers than does the fictional hero. … Much of the historian’s work then, like that of the insurance investigator, the fingerprint man, or the coroner, may to the outsider seem to consist of deadening routine … yet the routine must be pursued or the clue may be missed, the apparently false trail must be followed in order to be certain it is false; the mute witnesses must be asked the reasons for their silence, for the piece of evidence that is missing from where one might reasonably expect to find it is, after all, a form of evidence itself. … We are all detectives, of course, in that at one time or another we all have had to engage in some genuine deductive routine. Each day we do so, if only in small ways. By the same token, we are all historians, in that we reconstruct past events from present evidence, and perhaps we build usable generalizations upon those reconstructions. 4

Attention will now be turned to the scientific method; then to the means for reconstructing the past.

The Scientific Method

Evolving from the efforts of many workers over the course of several thousand years, the scientific method is a way of observing, thinking about, and solving problems objectively and systematically. As the prestigious nineteenth-century student of science Thomas Huxley emphasized, its use is not limited to scientists. A lesson Huxley learned early was “to make things clear,” and his easy, plain-talking style in the opening paragraphs of this piece serves well as an introduction to the scientific method.

The method of scientific investigation is nothing but the expression of the necessary mode of working of the human mind. It is simply the mode by which all phenomena are reasoned about, rendered precise and exact. There is no more difference, but there is just the same kind of difference, between the mental operations of a man of science and those of an ordinary person, as there is between the operations and methods of a baker or of a butcher weighing out his goods in common scales, and the operations of a chemist in performing a difficult and complex analysis by means of his balance and finely graduated weights. It is not that the action of the scales in the one case, and the balance in the other, differ in the principles of their construction or manner of working; but the beam of one is set on an infinitely finer axis than the other, and of course turns by the addition of a much smaller weight. You will understand this better, perhaps, if I give you some familiar example. You have all heard it repeated, I dare say, that men of science work by means of induction and deduction, and that by the help of these operations, they, in a sort of sense, wring from nature certain other things, which are called natural laws, and causes, and that out of these, by some cunning skill of their own, they build up hypotheses and theories. And it is imagined by many, that the operations of the common mind can be by no means compared with these processes, and that they have to be acquired by a sort of special apprenticeship to the craft. To hear all these large words, you would think that the mind of a man of science must be constituted differently from that of his fellow men; but if you will not be frightened by terms, you will discover that you are quite wrong, and that all these terrible apparatus are being used by yourselves every day and every hour of your lives. 5


Before proceeding to an example of the scientific method in criminal investigation, several terms require definition (see Box 14.1). They are: induction, deduction, classification, synthesis, analysis, hypothesis, theory, a priori, and a posteriori.

Box 14.1

Some Key Definitions

Inductive Reasoning – The process of reasoning beginning with specific information to form a general conclusion.

Deduction – The process of reasoning that begins with a generalization and moves to a particular or specific conclusion (fact).

Classification – The systematic arrangement of objects into categories that have one or more traits in common.

Synthesis – The combining of separate parts or elements that lead toward a conclusion.

Analysis – Examines all information available in an effort to separate the data into relevant parts for further study.

Hypothesis – Forms the basis for an examination of information to form an assertion or tentative guess.

Theory – A scheme of thought with assumptions chosen to fit empirical knowledge or observations.

A priori  – Deductive or theoretical reasoning based on cause and effect, where a conclusion is based on self-evident principles.

A posteriori  – Inductive reasoning based on empirical facts acquired through experience or experimentation to form general principles.

Induction is a process of reasoning based on a set of experiences or observations (particulars) from which a conclusion or generalization is drawn. It commences with the specific and goes to the general. As to the result secured, however, care must be exercised. This warning is implicit in Huxley’s “sour apple” lesson. For another illustration, consider the man who notes that of the 10 species of bird he has observed, all are able to fly. When he induces from this observation that all birds fly, he will be incorrect. Though not always recognized as such, the penguin is a bird. At one time, its short paddles covered with hard, close-set feathers served as wings. Now, it moves swiftly and gracefully through water, having over the eons become adapted to this medium; the penguin does not fly. The ostrich is another example of the fallacious conclusion that all birds fly. Induction, therefore, can lead to probabilities, not certainties. When integrated over a lifetime, however, inductive experience is an important component of the so-called common sense that supposedly governs human behavior.

Deduction is a process of reasoning that commences with a generalization or a premise and by means of careful, systematic thinking moves to a particular fact or consequence. For example, if one begins with the statement that “All persons convicted of a serious crime are felons” (the major premise), then adds the fact that “Jack was convicted of a serious crime” (the minor premise), that “Jack is a felon” (the conclusion) may be deduced. This is a syllogism, a form of deductive reasoning that moves from the general to the specific. If the original premise is valid, the logical consequences must be valid. In logic (the science of correct reasoning), deduction leads to certainties and not to probabilities; in criminal investigation, the generalization cannot be so precisely formulated as to always be relied upon as valid. Only in fiction is a Sherlock Holmes able, after a quick glance at the mud on the butler’s shoe, to state unequivocally that it originated from but one meadow. In the real world, the criminal investigator cannot mouth certitudes while an awed partner (like Dr. Watson) stands by and accepts them on faith. Because of the illogical, often perverse quality of human behavior, deduction does not necessarily lead to certainty.

Classification is the systematic arrangement of objects into categories (groups or classes) based on shared traits or characteristics. The objects in each category, having one or more traits in common, are chosen to suit the classifier’s purposes. They may be natural (in accord with the observed order of things), logical, or even purely arbitrary. The science of classification is called taxonomy. Biology has developed a taxonomy to classify organisms; chemistry, to analyze compounds; law enforcement, to file fingerprints, bullets, DNA, a wide range of typefaces, and automobile paints.

Synthesis is the combining of separate parts or elements. For purposes of criminal investigation, those elements that, when combined, provide a coherent view of the crime and its solution, are: the evidence provided by witnesses, forensic examinations, and the facts disclosed by records.

Analysis starts with the whole (whether a material substance, thought, or impression), and then involves an effort to separate the whole into its constituent parts for individual study. Hence, on being assigned to investigate a crime, the investigator seeks relevant information from three separate sources—people, records, and the physical evidence found at the crime scene.

hypothesis is a conjecture that provisionally accounts for a set of facts. It can be used as the basis for additional investigation and as a guide for further activity. Because it is an assertion or tentative guess subject to verification, the pursuit of more evidence is required of the detective (or scientist). Along the way, the hypothesis may have to be adjusted, causing the investigation (or inquiry) to change direction depending on whether the original conjecture is substantiated or disproved as new facts are uncovered. As corroborating data accumulate and are analyzed, the hypothesis moves toward the next phase of proof—a theory.

theory is a somewhat verified hypothesis, a scheme of thought with assumptions chosen to fit empirical knowledge or observations. As a theory becomes more solidly based and evidence accumulates, it evolves into a methodical organization of knowledge applicable to any number of situations. It should predict or otherwise explain the nature of a specified set of phenomena. The ultimate theory presents a grand conceptual scheme that both predicts and explains, while keeping assumptions as few and as general as possible. In science, the ultimate is often achieved; in criminal investigation, a less decisive “somewhat verified hypothesis” is the best that can be expected at the present time.

A priori (Latin for “from the previous cause”) is defined: from a known or assumed cause to a necessarily related effect; from a general law to a particular instance; valid independently of observation. In some instances, a priori conclusions are reached through reasoning from assumed principles, which are regarded as self-evident. Thus, it is deductive and theoretical rather than based on experiment or experience.

A posteriori is a term denoting reasoning from empirical facts or particulars (acquired through experience or experiment) to general principles; or, from effects to causes. It is inductive.

Problem Identification

The first step in reconstructing the past or unraveling the mysteries of the universe is to identify the problem. What is the question? Although the techniques and methods for problem-solving have been systematized as the scientific method, the state of affairs regarding problem identification—namely, recognizing what it is, precisely—is less than satisfactory. Indeed, operational research, which is concerned with correctly stating the problem to be studied, was conceived of in England by scientist J.D. Bernal when he solved a problem submitted by the military during World War II. Informed that his solution did not work, Bernal investigated further only to find that, although he had solved the problem given him, it was not what was actually troubling the military. Painstakingly, he was obliged to reformulate and restate the problem for them before the solution could be applied.

Texts dealing with public relations reveal that problem identification is a major concern. It begins with an interview of the client to ascertain what the problem is believed to be. Then, a search of the literature is made to learn more about the apparent issues. Finally, there is an attempt to restate the problem. This procedure is the basis on which an effective public relations program can be developed.6Although problem identification is seldom the concern of the criminal investigator, the problem statement pertains to two situations in the criminal justice system. One occurs when a crime is committed on the borderline of two jurisdictions; the other, when it is difficult to determine what crime was committed. If it is a question of jurisdiction, an investigator may either seek to obtain the case, or convince the investigator working the other jurisdiction to accept it. The choice can depend on several factors: Is the case likely to be publicized? Is it inherently interesting or important? Is there a chance to make a “good arrest”? As to determining what crime was committed, this is usually quite simple because the elements of major crimes (burglary, robbery, murder, manslaughter, assault, rape, and arson) are well-known to the experienced investigator. However, the increasing use of computers, the Internet and social media have added a new dimension to criminal investigation that may well be less defined. This is further complicated by the fact that most criminal activity using computers or the Internet involves more than one jurisdiction, frequently making the activity a federal crime— where the federal government may have jurisdiction, or in some cases involving transnational criminality jurisdiction may be questionable. The advice of legal counsel is advisable, however, when the determination is a complicated one: Is it a case of extortion or third-degree robbery? In crimes involving consent, such as fraud, was consent granted or withheld? Does the mere scorching of the paint on a house, without fire, satisfy an element of arson? Or does an Internet threat amount to extortion?

Scientific Reasoning Applied to a Criminal Investigation

The use of the scientific method in criminal investigation is illustrated by the following situation, based on an actual case. A detective, called to the scene where a young woman had been murdered in her apartment, found the table set for two. There were melted-down candles, wine, supper still warm on the serving cart, and a radio softly playing. Finding no evidence of forced entry or struggle, the detective hypothesized that the woman admitted the killer into her home, probably as her dinner guest. In subsequent questioning of the victim’s family, friends, and business associates, one name, that of her former lover, continually surfaced; indeed, several people indicated that his earlier behavior during a quarrel had been forgiven, and that this was to have been a reconciliation dinner.

The hypothesis that the killer was an invited guest is somewhat verified by the facts obtained through interviews. Needing additional information, however, the investigator must consider the following possibilities: Can the friend be located at his place of business, home, or other usual haunts? Is flight indicated? If so, is any clothing or other item such as razor or prized trophy missing? Did the suspect cash a large check or withdraw money from his bank the day of or on the morning following the homicide? If affirmative answers are obtained and applied inductively, the weight of evidence in support of the hypothesis is even greater. The former lover may now be considered the prime suspect (the generalization). An inductive result, however, is not necessarily a certainty: flight may be evidence of guilt, but it is not proof. The suspect could have innocently gone on a vacation at what would, in retrospect, have been an inopportune time. Assuming that information from relatives and friends has failed to trace him, the homicide investigator must now discover his whereabouts.

The next logical step in the investigative process is deduction. The characterization of the lover as the prime suspect (the generalization) leads to the question: “Where would he be likely to flee?” (answers to which are the particulars). Possible locations are suggested by such considerations as: Where was the suspect born? Had he lived for a time in some other area? Does he have a favorite vacation spot? With additional facts or details elicited, investigative activities will seek answers (again, particulars) to other questions, such as: What else might he do to earn a living? Who might he write or telephone? Will he try to collect his last pay check either by mail or other means? Will he continue to pay union dues? Will he change his driver’s license? A sufficient amount of acquired and utilized facts (particulars) should allow the investigator to come to a generalization through the process of inductive reasoning.

The generalization about the likely whereabouts or location of the subject permits the investigator to deduce the particulars (such as addresses) needed to apprehend the suspect. Again, reasonable premises (e.g., that suspects will turn up at their usual haunts) may prove to be invalid because of the illogical, often perverse aspects of human behavior.

In summary, the cyclical process of scientific reasoning—moving from induction to deduction, and vice-versa—is applicable to criminal investigation as a means of reconstructing past events. A noted philosopher of science, Hans Reichenbach, recognized the similarities in the thought process shared by scientist and detective:

I should like to mention the inferences made by a detective in his search for the perpetrator of a crime. Some data are given such as a blood-stained handkerchief, a chisel, and the disappearance of a wealthy dowager, and several explanations offer themselves for what has happened.

The detective tries to determine the most probable explanation. His considerations follow established rules of probability; using all the factual clues and all his knowledge of human psychology, he attempts to arrive at conclusions, which in turn are tested by new observations specifically planned for this purpose. Each test, based on new material, increases or decreases the probability of the explanation; but never can the explanation constructed be regarded as absolutely certain. 7

Reconstructing the Past: Sources of Information

The information needed to reconstruct the past is available through three sources: people, physical evidence, and records. Historians’ efforts to shed light on the distant past are largely confined to researching records. Art and epic poems (physical evidence) and folk tales (people) are also researched. Criminal investigators, more concerned with the immediate past, often put all three sources to use. Table 14.1 summarizes and compares the sources of the historian and the criminal investigator.

Table 14.1

History and Criminal Investigation as Methods of Study of Past Events: Sources of Information Common to Both; Available Ancillary Disciplines



As long as general, specific, or intimate knowledge concerning an individual endures, it can be acquired by those who know how. People are social beings, and information on them can usually be found in the possession of family and relatives, work or business associates, and others who share their recreational interests. It can also be picked up accidentally through those who were witness to, or the victim of, a crime. The careful investigator identifies and exploits all potential sources. Some people will talk willingly; some will be reluctant to disclose what they know. Investigators must learn how to overcome resistance and retrieve facts that were overlooked, forgotten, or thought not important enough to mention. Meanwhile, they must guard against deliberate distortions or attempts to mislead, thwarting such maneuvers through skillful questioning. Talking with people and unobtrusively observing them and the places they frequent may be useful. Tips or decisive information furnished by informants can also be significant in moving an investigation toward a conclusion.

Physical Evidence

Any object of a material nature is potential physical evidence. The scientific specialties that undertake most examinations of physical evidence are forensic medicine and criminalistics. Their purpose being the acquisition of facts, the following questions arise: What is this material? If found at a crime scene, can it be linked to, or help exonerate, a suspect? Can it be used to reconstruct what happened (especially when witnesses give conflicting accounts)? In a homicide, what was the cause of death?

In the conduct of everyday affairs, people employ physical evidence in decision making, but few note this fact. For example, when looking for a house they will examine the condition of the paint, plaster, and plumbing; determine its location relative to transportation, schools, and churches; then inspect the surrounding neighborhood. The ultimate decision is based to a large extent on this kind of evidence; indeed, it is the way many day-to-day decisions are made.


Records are a form of physical evidence. They receive separate treatment in this text, however, because they are widely scattered, voluminous, and have specialists devoting full time to their storage and retrieval. Modern society relies on both paper and electronically stored records by amassing the information collected day in and day out. Later this can prove useful in a criminal investigation. For example, telephone company records of toll calls can establish that two people who deny any relationship had indeed been in communication. Records need not be printed or handwritten. They may be stored in digital form or on film or tape. One famous historic example is the White House tapes that provided the “smoking gun” evidence in the Watergate cover-up of the Nixon Administration.8This case clearly demonstrates the power of physical evidence over verbal testimony.

Innovative Applications

History and archeology are academic disciplines that reconstruct the past through information from people, physical evidence, and records. Some unusual investigative efforts employing classical techniques have gained attention in the press as well as in scholarly literature. They demonstrate that the means for reconstructing the remote past are applicable to the immediate past. Hence, criminal investigation is not unique; it shares the approaches sanctioned by scholars in established disciplines. The following examples will illustrate.

Industrial Archeology

Uncovering traces of an ancient civilization in a temple or amphitheater sounds more romantic than finding what remains of an old factory. Yet the classical techniques of archeology are now being used

… to discover and record how American industry moved from colonial cottages to the vast mechanized and automated complex it is today. Although the industrial revolution began in the U.S. only about 200 years ago, there already are tremendous gaps in the knowledge of how it occurred.

Records and artifacts of entire industrial processes, including some in use as recently as the 1920s, either have been lost or, often, were never made. And the machines and buildings that would give clues to how an industry evolved are rapidly being destroyed or buried by parking lots, housing developments and new factories. If Patterson (New Jersey) is any indication, American cities are being buried several times faster than ancient Troy; the archaeologists in Patterson found foundations barely a century old at depths of eight to twelve feet. … It took over 5000 years for fifty feet of debris to build up over ancient Troy. 9

Lest such behavior be thought of as that of a few eccentric archaeologists, it is significant to note that more than one university has set up an Institute of Industrial Archeology.10


Another contemporary form of archeology is garbageology, the “science of rubbish” or the study of garbage.11 Discarded material can be revealing when analyzing present-day consumer trends. So too are the different facets of a family’s shopping habits, better disclosed through the study of its trash than through buying surveys. There is, however, the issue of an individual’s right to privacy, even though refuse left on a sidewalk is abandoned property and its removal not theft. The journalist who took five plastic bags of trash left in front of a celebrity’s home unwittingly gave fresh meaning to Shakespeare’s lines: “Who steals my purse steals trash; ’tis something, ’tis nothing,” for Iago knows only too well that the trash will indeed “filch … [his] good name.”12 Whether from contemporary rubbish or the ruins of antiquity, reconstructing the past can reveal how people live(d).

Theological Detective Work

Candidates for sainthood in the Catholic Church undergo an investigation that has been described as “theological detective work.”13 To be declared a saint, a candidate must “… have to be responsible for two miracles, specifically medical miracles.”14 Scrutinizing such candidates involves performing archival searches; sifting through diaries, poems, and letters; and interviewing people. Because an important goal is to find a stain on the candidate’s character, theological detective work is akin (in the reverse sense) to criminal investigation wherein the protection of the innocent has an equal claim. As a process of inquiry, beatification is always exhaustive and expensive. Like criminal investigation, it has its share of critics who claim there are better ways to spend time and resources.

This brief survey of a few novel examples of inquiry suggests that the study of criminal investigation is not one of narrow vocational interest; instead, it lies within the educational tradition that produces generalists rather than narrow specialists. Because industrial archeology, garbageology, and the process of canonization share the same purpose—that of reconstructing the past—the astute student will perceive that what is learned through the study of criminal investigation can be applied to a broad range of theoretical and practical problems.

Data Mining and Information Gathering

Data mining involves the use of computers or data secured from private companies to explore and retrieve information that can be analyzed to form conclusions about potential suspects or types of criminal activity. Information gathering involves the collection of information on individuals or groups who may be involved in, or familiar with others involved in, criminal activity. This borders on the problem of profiling when the focus is on a particular race or religious group, and has been the subject of criticism of police focusing on Muslims, or on young blacks or Hispanics in connection with gang activity.

Data mining also involves the use of relational databases, artificial intelligence, and algorithms to test theories and formulate probability estimates. In the business sector, for example, by determining what types of periodical subscriptions, online purchases, and credit purchases an individual makes, a profile can be determined about his or her personal, career, and purchasing interests; psychosocial preferences; and movement (travel). This information is frequently sold or shared between companies, and is a major factor in marketing.

In criminal investigation, profiles of pedophiles and online child pornography rings have been successful avenues of pursuit. Relational databases and linking programs also provide a means of examining large amounts of information to identify suspects and their contacts with others.

Caution must be taken in this area, given the concerns about law enforcement invading the private lives of citizens. The courts and Congress have been critical of some of the tactics involved in seeking to identify terrorists by using data mining or questionable information-gathering techniques.

Further Commentary on the Investigative Process

Peripheral issues surface from time to time regarding the investigative process. They involve such questions as: Is luck important to the outcome of an investigation? Is a skeptical attitude of value to an investigator? Is there such a thing as an investigative mind-set? Some cases and examples are provided below to illuminate these issues.

Luck Or Creativity

Rather than merely an exercise in objective, systematic thinking, criminal investigation is believed by experienced detectives and some scholars of the investigative procedure to involve an element of luck.15 As careful analysis will suggest, it is not good fortune alone. It is “chance which can be on our side, if we but stir it up with our energies, stay receptive to its every random opportunity, and continually provoke it by individuality in our hobbies and our approach to life.”16 William Beveridge devotes an entire chapter to this matter, which he summarizes as follows:

New knowledge very often has its origin in some quite unexpected observation or chance occurrence arising during an investigation. The importance of this factor in discovery should be fully appreciated and research workers ought deliberately to exploit it. … Interpreting the clue and realizing its possible significance require knowledge without fixed ideas, imagination … and a habit of contemplating all unexplained observations. 17

See Box 14.2.

Box 14.2

Two Case Studies Show the Unknown Factor of Chance

Case One:

This case involved an aged widow, a recluse living in an apartment-hotel. Her meals delivered daily, the evening tray would be placed in her locked foyer by the night shift elevator operator. After he left she would retrieve the tray, and upon finishing, replace it in the foyer to be picked up several hours later. Occasionally, the night shift operator had an opportunity to talk with the woman, but then only briefly. When the evening tray had not been replaced even by breakfast time, and the morning tray had remained untouched, the day shift operator notified the building manager. Using a pass key, the manager found the woman apparently dead on the bedroom floor; on the kitchen table were the remains of the evening meal of the previous day. The medical examiner established that she had been strangled. It was a case of criminal homicide.

The day shift operator was questioned but could supply no useful information; other tenants had not seen or heard anything suspicious. Checking out the victim’s background, friends who visited, and other possible leads occupied the investigators for the remainder of the day. They then focused their questions on the night shift operator who had delivered the last tray of food she had touched. Except for her failing to replace it, he observed nothing unusual, he said, adding that even this had not surprised him, because it was not the first time it had occurred. Asked to account for his own dinner hour, he reported that it had been meatloaf as usual at the corner cafeteria; after that, a smoke on the street outside the restaurant.

To the detectives assigned to the case it looked like a protracted investigation. As they returned to the station house close by and passed the cafeteria, one of the two suggested, “Let’s check on the operator’s story, and see if anybody remembers seeing him last night.” The slight possibility that he had not had dinner there was dashed when the cashier, the owner’s wife, stated unequivocally that she had seen him: “He always comes in when he works. He likes our food and prices.” The detective probed further, inquiring about the meatloaf served the previous night. The cashier’s reply was a surprised, “It’s odd that you ask. Yesterday we had trouble with the ovens and the cook couldn’t bake. It’s the first time in more than a year that meatloaf was not our Thursday night special.” Needless to say, the detectives did not continue on their way back to the station house; instead, they quickly returned to the hotel to conduct an intensive interrogation of the night shift operator.

Was it chance or was it thoroughness that prompted the check on the man’s story? Had chance prompted the inquiry about the meatloaf? Had experience suggested the most trivial of statements be verified?

Case Two:

This case started innocuously enough when a U.S. Army .45 automatic pistol disappeared from a tavern in a small university town. The detective who responded to the report made proper notifications (within the department and to other law enforcement agencies) pertaining to gun theft, but did little else. A month later, however, an armed robbery occurred in a bank 20 miles away; the weapon the robber brandished, a U.S. Army .45 automatic. The disappearance of the pistol from the tavern still unsolved, and there being no clues except for the eyewitness descriptions of the bank robber, the federal agent assigned to the case decided to follow up on the uncleared gun theft.

The agent’s diligence uncovered the information that a carpenter had been working in the back of the tavern during the time the gun disappeared. On the outside chance that the carpenter had seen or heard something, the agent made an appointment for an interview at his home. Arriving early and invited in by the carpenter’s wife, he observed a photograph on the piano. Its smudged surface had caught his eye. “Is that a picture of your husband?” he inquired. Walking over to it, she answered, “Yes, it is. And you know, he did a dumb thing a few days ago. He ruined it trying to see how he would look with a mustache. He never had one before. Then he tried to erase the marks, and now look what he’s done!” It was not surprising that the woman saw only the damage done to a cherished possession. But to an investigator who had acquired the habit of scrutinizing seemingly trivial details and contemplating unexplained observations, the implications of her husband’s need for a disguise were clear. Until then the man in the photograph had not even remotely been a suspect. When placed in a lineup, there was an eyewitness identification of the carpenter; this, followed by an interrogation, led to a confession.

Beveridge drew on Pasteur’s well-known aphorism, “In the field of observation, chance favors only the prepared mind,” when he wrote:

It is the interpretation of the chance observation which counts. The role of chance is merely to provide the opportunity and the scientist has to recognize it and grasp it. 18

In any investigation, it is easier to perceive clues or hints when the mind is prepared through interest or experience. As already suggested, a creative, albeit critical, nature is also helpful for suspecting potential or actual criminality.

Investigative Mind-Set

Just as hindsight brings clear vision, so does investigative mind-set provide foresight, and possibly insight, to the creative investigator. The terms mind-set and a set mind are antithetical; one should not be mistaken for the other. A set mind is scarcely useful to the investigator, the cerebral faculty being neither developed nor strengthened by an inflexible outlook. Investigative mind-set on the other hand, is to some extent a gift at birth. It can, however, be developed through practice and experience. More than mere suspicion, it is doubt or misgivings based on experience that, in combination with a critical faculty, often perceives a connection between two apparently unrelated items or bits of data, and looks for what does not fit the situation. What exactly is wrong? Is there anything out of place? Unusual? If so, why? Two maxims speak to the practical value of a skeptical outlook: such old proverbs as the Latin “Believe nothing and be on your guard against everything,” and the Persian “Doubt is the key to knowledge.” The philosopher René Descartes developed a theory of knowledge based on doubting everything—including his own existence. He said, “I think, therefore I am,” employing the aphorism to show how the doubt had been resolved to his satisfaction. Examples of investigative mind-set are found in the 9/11 World Trade Center case.

These details about intelligence gathering suggest that some attributes are shared by criminal investigators and intelligence agents, even though one is reacting to a crime already committed, while the other is trying to fathom future activities of a targeted person. These shared characteristics include:

• Investigative mind-set

• Interrogation methods

• Surveillance capabilities—including technical means

• Perseverance

• An ability to “think outside the box”

Box 14.3

A Case Study Shows the Value of Investigative Mind-Set

The 9/11 World Trade Center Attack

The terrorists who leveled the World Trade Center on September 11, 2001 were, in retrospect, able to enter, leave, and explore the country for potential opportunities that would allow them to accomplish their villainous goals. One prospect was to enroll as students in pilot flight training schools. They showed little interest in learning how to take off and land; rather, they wanted to learn how to pilot a commercial jet while airborne. Anyone with an investigative mind-set would regard this behavior as suspicious. Two FBI agents did so. One, on July 10, 2001, sent a communication to headquarters “outlining links between a group of suspected Middle Eastern terrorists and the Embry-Riddle Aeronautical University … The agent (Kenneth Williams) … suggested that the FBI should canvass U.S. flight schools for information on other Middle Eastern students. He speculated that bin Laden might be attempting to train operatives to infiltrate the aviation industry.”a The other agent, Coleen Rowley, a Minneapolis field office lawyer, sent a 13-page letter to the newly appointed Director of the FBI warning him about, among other things, how “instructors at the Pan Am flight school near Minneapolis–St. Paul had phoned the FBI the previous day reporting that a student, in bad English, had showed up asking for instruction on how to fly a 747.”b When FBI agents arrived at the student’s motel, they asked for his immigration papers. “[W]hen the documents showed evidence of a possible visa violation, agents from the Immigration and Naturalization Service arrested (Zacarias) Moussaoui on charges of overstaying his visa.”c Despite evidence obtained from French intelligence that Moussaoui “was not only operational in the militant Islamist world but had some autonomy and authority as well,”d Rowley’s request for permission to obtain a search warrant to study the contents of (Moussaoui’s) laptop was denied by a superior at headquarters. “Only after September 11, 2001, did the FBI successfully obtain a warrant to search Moussaoui’s belongings; among other things the search turned up crop dusting information … and a notebook that contained an alias eventually traced to the roommate of hijacker Mohammed Atta.”e


Apprehended terrorist Zacarías Moussaoui. U.S. Department of Justice

It is perhaps relevant to remark at this point on the relationship between criminal investigation, which is a reactive endeavor, and intelligence, which is a proactive endeavor.

“It was old-fashioned interrogation and eavesdropping that first led U.S. agents to the Qaeda [sic] plotters. In the summer of 1998, only a couple of weeks after bin Laden operatives truck-bombed two U.S. Embassies in Africa, the FBI got a break: one of the Nairobi bombers had been caught. … (He) was supposed to have killed himself in the blast. Instead, he got out of the truck at the last moment and fled. He was arrested in a seedy Nairobi hotel, … (and) questioned by the FBI, … Among the information he gave agents was the telephone number of a Qaeda [sic] safe house in Yemen … U.S. intelligence agents began listening in on the telephone line of the Yemen house, described in government documents as a Qaeda [sic] ‘logistics center,’ where … the African bombings and later the Cole attack in Yemen—were planned. … [I]ntercepted conversations on the Yemen phone tipped off agents to the January 2000 Kuala Lumpur summit [meeting].… After the meeting, Malaysian intelligence continued to watch the condo at the CIA’s request, but after a while the agency lost interest. Had agents kept up the surveillance, they might have observed … Zacarías Moussaoui.”f

Zacarias Moussaoui pleaded guilty to all charges against him (conspiracy to commit acts of terrorism transcending national boundaries, to commit aircraft piracy, to destroy aircraft, to use weapons of mass destruction, to murder U.S. employees, and to destroy property). He was sentenced to six consecutive life terms without the possibility of parole. In early 2010, a federal appeals court denied his appeal and affirmed the conviction and life sentence.


aBarton Gellman. “Dots That Didn’t Connect,” The Washington Post National Weekly Edition, (May 27–June 2, 2002), 10.

bR. Ratnesar and M. Weisskopf, “How the FBI Blew the Case,” Time, (June 3, 2002), 28.

cLoc. cit., col. 2.

dLoc. cit., col. 3.

eIbid., 31, col. 3; 32, col. 1.

fM. Isikoff and D. Kaidman, “Terrorists Who Got Away,” Newsweek, (June 10, 2002), 24, 25.

The Development Of Mind-Set

In day-to-day reading, a news story occasionally triggers the mind to question its details and reflects a developing investigative mind-set. If articles are clipped and files maintained as stories unfold, original suspicions may be confirmed or denied. As the reader’s ability improves through practice, more validations and fewer misjudgments will occur.

Conscientious students will find that the study of old newspaper and magazine files in libraries and “surfing” the Internet helps stimulate those intuitive responses that characterize investigative mind-set. A great deal of time may be required to find suitable case examples, but with patience—a primary investigative attribute—there is intellectual gold to be mined.

What evidence and proof consist of in science, law, and criminal investigation are the subject of the next section. Table 14.2summarizes this information.

Table 14.2

Evidence and Proof: In Science, Law, and Criminal Investigation a



aAlthough depicted as seven categories for didactic reasons, such a division may also (and should) be viewed as a continuum.

bReasonable Suspicion. A category of proof that is less than probable cause but more than speculative, it was invoked by the managers for the House of Representatives in the impeachment and trial of President William Jefferson Clinton. This category of proof is not recognized in science.

cThe U.S. Supreme Court has not looked favorably upon attempts to define “beyond a reasonable doubt” because it found the words themselves sufficiently descriptive. (Consult Miles v. United States, 103 U.S. 312 (1981)). “Beyond a shadow of a doubt” is a colloquial term that falls between Categories VI and VII. Proof “beyond a shadow ofany doubt” falls into Category VII.

dCircumstantial evidence falls into Category III-VI. It is evidence not bearing directly on the fact in dispute, but on various attendant circumstances from which a judge or jury may logically infer the occurrence of the fact in dispute. It is indirect evidence by which a principal fact may be arrived at inductively. It is far more common than direct evidence, i.e., eyewitness testimony or a confession.

eThis standard of proof was invoked in the political impeachment of President Richard Milhous Nixon.

Evidence and Proof

A chance observation, such as a detective’s noting the marred surface of a photograph (as in the case of the U.S. Army pistol theft), represents an investigative opportunity. It does not constitute evidence of probable cause. Sometimes chance may raise a mere suspicion, a sense that the nature or quality of what is observed presents “interesting possibilities” worthy of follow-up. To be of further value to the investigator, it must be supplemented by an apperceptive noting and recording of facts—seen and understood in the light of past experience. The chance observation and apperception coming together in this process inductively provide grounds for a hypothesis or a belief that leads to a tentative generalization. For example, a detective’s attention was called to a vehicle parked across the street from a bank, the bank president having observed it there several times in the past month. Additional suspicion was aroused when it was again seen an hour or so before opening time on one day, and just before closing time the following day. A check of its license plate revealed that the car was not stolen; its registered owner was a local resident with no police record. Despite this, the detective, acting on a sense of “interesting possibilities” in the nature of what had been observed, briefed the radio car patrol covering the car owner’s residence about the bank’s uneasiness. A week later the sector car patrol officer spotted an out-of-state vehicle parked in the driveway of the house. A check disclosed that the vehicle was registered to an individual with a bank burglary record, whose modus operandi was to burn around the dial of a safe with an acetylene torch.

By now, the detective’s thinking had moved by degrees from the mere suspicion or “intriguing possibilities” stage to one that at the very least called for some follow-up measures. Official interest was still based on speculation however, with additional facts needed to prove that the bank was indeed to be “hit.” Local welding equipment suppliers were alerted and provided with photographs of both individuals. As prearranged, when a customer resembling either one came in for a tank of acetylene, police were alerted and surveillance of the purchaser—now a suspect—was begun.

It is clear from the foregoing that evidence consists of a number of facts that point to a conclusion. In this case, if the bank is broken into, that fact would prove intent to commit burglary, but if the detective waits for the suspect to emerge, loot in hand, it would provide sufficient evidence to support and prove the charge of burglary. The number and kind of facts, together with the ambiguity or doubt associated with each fact, dictate the level of evidentiary value. When enough facts are available, proof becomes possible depending upon the purpose, criteria, and requirements of the discipline in which the proof is offered. As pointed out earlier, Beveridge suggests discoveries result when attention is paid to the slightest clue. A certain attitude of mind (capable of a quantum leap from limited evidence) is required for the discovery stage, whereas the unquestioned proof stage has distinctly different evidentiary requirements. In criminal investigation, similarly, there are two standards of proof: “probable cause” for a legal arrest and “beyond a reasonable doubt” for a conviction. In civil cases the standard is “a preponderance of the evidence”; the House Judiciary Committee in its impeachment deliberations proposed as the yardstick “clear and convincing” evidence.19 Although each standard seems discrete, it should be viewed as a continuum of evidence and proof.

Evidence, then, is the means by which a fact is established. When the number of facts collected and confirmed is sufficient, depending on whether it is a civil or criminal matter, the point in question is proved. In civil law, a preponderance of the evidence is required; in criminal law, it must be “beyond a reasonable doubt” (see Table 14.2).

Conclusion: Investigation—Art Or Science?

The concept of continuous succession—a continuum—is helpful in understanding other aspects of the investigative process; specifically, to examine two polar views: investigation as an art versus investigation as a science. But if art and science are part of a continuum, where does the separation point lie? Further reflection suggests it is determined by the subject under consideration: for the physical and biological sciences, it is far to one side; for culinary creativeness, it leans toward the arts (since any chef can read a cookbook and follow directions). For criminal investigation, the separation point is moving by degrees toward science. The field is becoming a focus of academic study and research, one in which the impact of forensic science is felt more and more. See Box 14.4

Box 14.4

Summary of the Scientific Method and Its Application to Criminal Investigation

The Steps Involved may be Summarized as Follows:


*Criminal investigation generally commences as an inductive process with deductive reasoning integral to it.

**Problem recognition precedes this stage and is, perhaps, the driving force leading to an investigation of the problem. As part of the process, the issue must be clearly formulated by “stating the problem.”

Important Case

Miles v. United States (1981)

Discussion Questions

1. What is the scientific method?

2. What is inductive reasoning?

3. What is deductive reasoning?

4. What is the difference between classification and synthesis?

5. What is the difference between a hypothesis and a theory?

6. What is data mining?

Supplemental Readings

1. Barzun J, Henry FG. The modern researcher 6th ed. Belmont, CA: Thomson/Wadsworth; 2004.

2. Copi IM, Cohen C. An introduction to logic 14th ed. Upper Saddle River, NJ: Pearson/Prentice Hall; 2010.

3. Davidson JW, Mark HL. After the fact: The art of historical detection 6th ed. Boston: McGraw-Hill; 2009.

4. Fisher D. Hard evidence: How detectives inside the fbi’s sci-crime lab have helped solve america’s toughest cases New York: Simon & Schuster; 1995.

5. Kukura TV. Trash inspections and the fourth amendment. FBI Law Enforcement Bulletin. 1991;60(2):27–32.

6. Lang Jr AF, Beattie AR, eds. War, torture and terrorism: Rethinking the rules of international security. New York: Routledge; 2009.

7. Woodward KL. Making saints: How the catholic church determines who becomes a saint, who doesn’t, and why New York: Simon & Schuster; 1996.

8. Winks RW, ed. The historian as detective: Essays on evidence. New York: HarperCollins; 1978.


1W.B. Sanders, ed., The Sociologist as Detective (New York: Praeger, 1974).

2Robin W. Winks, ed., The Historian as Detective (New York: Harper & Row, 1969).

3Ibid., XXIV.

4Ibid., XIII, XVII, 4.

5Thomas H. Huxley, Collected Essays, Vol. II: Darwiniana (London: Macmillan, 1970), 363–365.

6E.L. Bernays, The Engineering of Consent (Norman, OK: University of Oklahoma Press, 1956), 9 ff.

7Hans Reichenbach, The Rise of Scientific Philosophy (Berkeley: University of California Press, 1951), 9 ff., 232.

8“The Republicans’ Moment of Truth,” Time, (29 July 1974), 10.

9J.E. Bishop. “Industrial Evolution,” The Wall Street Journal, (June 26, 1975), 40.

10R.A. Buchanan, Industrial Archeology in Britain (London: Penguin Books, 1972).

11J. Beck. “Study of Garbage Threatens Privacy,” Chicago Tribune, (July 18, 1975).

12“Trashy Journalism,” Time, (July 21, 1975), 40.

13L.R. Gallese. “The Good Fight: American Saint’s Cause Took Century of Work, Millions in Donations!” The Wall Street Journal, (June 25, 1975), 1, 19.


15Charles E. O’Hara and Gregory L. O’Hara, Fundamentals of Criminal Investigation, rev. 5th ed. (Springfield, IL: Charles C Thomas, 1973), 22.

16J.H. Austin. “The Roots of Serendipity,” Saturday Review World, (Nov. 2, 1974), 64.

17William I. Beveridge, The Art of Scientific Investigation, Modern Library rev. ed. (New York: Random House, 1957), 55.

18Ibid., 46.

19U.S. Congress, House Committee on the Judiciary, Hearings on H. Res. 803, 93rd Cong., 2nd sess. “Summary of Information,” 19 (July 1974), 5. “Debate on Articles of Impeachment,” 24, 27, 29, 30 (July 1974).


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