Principles of Investigation

Abstract

The purpose of an investigation is to determine something; to find out what, why, and who. A researcher searches for something new, an advance in the field of study. A doctor determines a diagnosis, a form of investigation. A police officer, at the scene of a motor vehicle traffic crash, or a burglary, or a suspicious death similarly investigates in order to determine what happened, what laws were violated and who was responsible. All these have one thing in common—the necessity to gather facts (data), assess their relevance and integrate them into a sensible and reasonable and correct conclusion. This requires expertise.

Keywords

Forensic pathology Death investigation Expertise

Expertise is a product of education, training and experience. Education should be broad in order for the investigator to understand principles of science, biology, and behavior, training to be able to use the necessary tools and experience in order to appreciate variations in patterns of circumstance, relationships between data and the ability to correlate data and anticipate future questions and their respective answers. Succinctly an investigator must have knowledge about the subject under investigation.

Equally important to knowledge is cognition. Cognition is wisdom, the ability to judge, to assess the value of data in one set of circumstances and its lack of value in another set of circumstances - “Book larnin” plus “street smarts”. The knowledgeable professor ensconced in isolated splendour may be extremely knowledgeable based upon learning and study of texts. Such an individual may be highly academic. A word of caution about academic - Webster's Third New International Dictionary includes definitions of academic as “of no practical or useful significance” and “very learned but inexperienced in or unable to cope with the world of practical reality”. The knowledgeable scholar may lack the ability to integrate knowledge into a logical and correct conclusion due to a lack of experience in day to day problem solving. Sometimes a psychological problem lies within the scholar or the investigator, a lack of cognitive ability.

Studies of the difference between good medical diagnosticians and those not so good have revealed a common error - over reliance upon non-contributory data. This is not confined to physicians. It may be found anywhere amongst lawyers, police, journalists, forensic pathologists, clergy, or in amongst members of any group which develops opinions as a matter of course. The expression “He is a linear thinker” describes an individual who jumps to conclusions during the early fact or information gathering phase, arrives at a fixed opinion and is oblivious to additional facts which support alternative more reasonable opinions.

The diagnostic approach to a medical problem is identical to any investigative problem. Tentative hypotheses, or investigative opinions are few in number and guide further inquiry. The two key elements in the successful completion of the investigation are adequate data and experience (1).

The more difficult problem, the more data is needed before opinion becomes useful as evidence. Anticipation of future questions or allegations should be considered part of the investigative process. Such anticipation will create the need for additional data to support the evidentiary opinion.

Principles of investigation require an ability to determine data sources, develop a data base, integrate data into the decision process and arrive at proper conclusions. Inherent in this process is the continual consideration of alternative explanations during the investigative process.

Death Investigation

An untoward event including death is not the result of a single cause but results from an interaction of factors. These factors exert influence over a continuum of time.

The analytical matrix of this concept was popularized during scientific analyses of motor vehicle crashes where factors were divided into human, vehicle and environment (the roadway). Time was separated into pre-crash, during the crash, and after the crash. From this approach one could determine the role of alcohol or drugs in crash causation, determine highway design or maintenance problems, or decide what vehicular design modification were needed.

Motor vehicle crash analysis is fairly simple in comparison to determination of “cause” of death and “manner” of death. People may die under an infinite number of circumstances. Multiple factors may be involved. Data acquisition may be limited by lack of data, legal restrictions or the capabilities of the investigators. To assure an adequate investigation it is well to develop an approach which considers events, people involved, and the environment.

Caution - most pathologists are taught to interpret autopsies but are not taught to interpret circumstances. In a hospital setting, with patient's clinical chart as a guide, the pathologist is given a data base - hospital chart plus autopsy - upon which to develop opinions as to cause of death.

In the real world of death investigation the data sources must be sought, the data acquired and the autopsy performed while circumstantial data is being accumulated. The circumstances must be considered if the autopsy is to be interpreted by the pathologist. Likewise, autopsy procedures and ancillary tests are circumstance dependent.

A scheme for data development and interpretation follows:

Circumstances

Witnesses Physical Evidence

Personal History

Social/Medical

Environment

Search Scene for Hazards

Circumstances: What was the victim doing when he/she became ill or died? Witnesses, neighbors, friends, family, have information of value to raise considerations or to limit extraneous considerations. Physical evidence found at the scene may permit a dynamic reconstruction of events in the absence of witness.

Personal History: Physicians are taught to take a history of the “present illness” and to list “past history”, e.g., previous operations, and illnesses, and use of tobacco, alcohol, and drugs. These are placed in the hospital record. In death investigation it is important to determine an expanded past history and particularly to determine the subset of society with which the victim was associated. A motorcycle gang member has risks of disease or injury not common to a certified public accountant. Certain subsets of employment are at risk of industrial diseases or injuries. Subsets of drug or chemical use create likelihood of intoxications. Prior medical or psychiatric histories likewise create a potential for consideration of causative factors in death.

Environment: Not all environments are benign. Fatal electrocution may occur without burns. Noxious gases may kill leaving few autopsy traces. Where - in what environment - the victim became ill or injured is a consideration. Sudden infant death syndrome is a category of puzzling death where infants, not expected to die nor seriously ill, are found dead. The autopsy is nonspecific. Occasionally the child has succumbed to an environmental hazard not readily apparent from the autopsy itself. When a person drowns, the issue is whether the watery environment was unusually hazardous, even to a skilled swimmer, or was the victim unusually deficient in swimming ability. Environmental considerations are a necessity in any death investigation.

The autopsy and toxicological studies should be conducted within the framework of available data. If the data indicates a potential for heart disease, for a toxin, for an infection, the autopsy procedures should focus upon these potentials.

The interpretation of the autopsy and toxicological findings must always be within the context of the totally available data - information derived from circumstantial, social and medical history and environment.

Example: A pathologist telephones a forensic pathology consultant with “I have performed an autopsy and I found …” At that point the forensic pathologist should interrupt and inquire as to name, age, race, marital status, occupation, and type of neighborhood in which the victim lived. This demographic data will begin to furnish an analytical approach to the problem.

The next question should be concerned with the circumstances; what was the victim doing when the terminal event began, what was witnessed, what was said and in what environment was this taking place. If a rescue squad was involved, what was documented - including the initial electrocardiogram (important in determining relevance of autopsy findings to a cardiac death).

Given the above information, a forensic pathologist experienced in scene investigation and total case evaluation ought to develop a reasonably good idea of what should have been done during the autopsy and how to interpret the autopsy findings. Only now should the caller be requested to list the autopsy findings.

Basically the principle of investigation is to create an analogy to the video play back utilized in televised football events. One views the action through different cameras and eventually can visualize what really took place during a complex activity.

In some situations it is valuable to review retrospectively the circumstantial data, ask what should be expected at autopsy and then compare with the autopsy findings.

Example: Two motor vehicles collide, one leaves the roadway and impacts a power line pole. The offending driver has no insurance. The utility company is the “deep pocket” in forthcoming litigation. Were the fatal injuries a result of the primary impact between vehicles or the later impact with the pole? One should assume there is no body, no autopsy, and should then analyze the crash kinematics. Now consider what injuries one would expect from such an event and compare this data with the autopsy findings. Such an analytical approach will serve to answer the question as to which impact was significant.

Documentation and Interpretation of Data

The steps at a death scene follow a logical sequence:

Documentation - Photography is best. The camera preserves a record of things which might not be noticed.

Recognition—Now the scene investigator realizes the significance of what is present. Often an experienced investigator will recognize before documentation but an orderly preservation of evidence requires documentation of everything, whether recognized or not.

Opinion—The analytical thought process begins as on evaluates evidence. At the scene initial opinions—subject to change—are investigative only. Later, after all evidence has been received, the opinion may be finalized into possible, probably, clear and convincing, scientific certainty, etc.

Essential to this process is correlation of all data (not just autopsy) and interpretation of future questions or allegations.

Retrospective Investigation

Investigators are frequently consulted by attorneys to review a concluded case and offer opinions which may or may not support the original opinion. This may involve a civil or a criminal matter. Usually the person making the request has accumulated a file of data and will offer same to the investigator.

It is essential that all the data be studied and not just what was initially proffered. The consultant's report should begin with an inventory of what was received, followed by a brief recapitulation and then questions and their responses. If more investigation is needed, that should be recommended. This report serves to summarize in easy to read format the case and assures that the data set is the same as those who would offer a contrary opinion. Although this procedure seems elementary, it is sorely needed.

Example: A defense attorney proffered an autopsy report plus autopsy photographs to a pathologist consultant. That consultant asked for the scene photographs, police reports, the background file of the initial medical examiner and microscopic slides. All this data revealed a set of circumstances and conclusions different from the original medical examiner pathologist. In fact, the initial pathologist had been given some erroneous information which may have affected his opinion. The trial, a homicide case, resulted in acquittal when it became clear that the initial police impression of the accident was correct. Subsequently, it was learned that the defense attorney had sought previous consultations from two forensic pathologists neither of whom requested scene photographs, police or medical reports or microscopic slides. Likewise, each rendered an opinion report in finality in less than thirty minutes!

Procedural standards for consultants in cases undergoing litigation may be needed. At the very least, investigators who proffer expert witness opinion should be aware that carelessness by an expert witness may lead to liability on the part of the witness (2).

Summation

Investigative principles require acquisition and interpretation of data derived from multiple agencies and personnel. This may only be achieved when the agencies have an established policy of interagency cooperation, procedures to assure correlation of all data, an awareness of each other's needs and abilities and trust between the agencies and their respective investigators.

Death investigation requires a satisfactory interaction between police detectives, crime scene technicians, crime laboratory personnel, forensic pathologists and toxicologists. In all criminal cases all of the above play a role. In apparent poisoning deaths the pathologist, detective, and toxicologist correlate their data. In apparent natural deaths, the detective and the pathologist may carry the responsibility. Under no circumstance does the pathologist, or the detective or the toxicologist, etc. singly carry out the investigation.

References

Elstein

A.S.

Shulman

L.S.

Sprafka

S.A.

Medical Problem Solving: An Analysis of Clinical Reasoning. Cambridge (MA): Harvard University Press, 1978.

Henderson Garcia

Legal and Ethical Considerations in Using Expert Witnesses in Litigation. In: Black

Klein

M.S.

Brunette

S.A.

, editors, Shepard's Expert and Scientific Evidence Quarterly. Colorado Springs (CO): Shepard's/McGraw-Hill, 1944. Page 717–726.