Counterposed with many other aspects of policing there is a comparative lack of research on homicide investigation. This is somewhat surprising given its predominance in both fictional and factual mass media representations of police work. Whereas media accounts of homicide investigation often portray detectives as able to solve cases through flashes of brilliant insight, the reality is often significantly different. The majority of homicide investigations typically involve and owe their success to meticulous, painstaking, and detailed work, following fairly standard organizational operating procedures. This routinization of investigative practice is structured by several problems that are regularly encountered and have to be resolved by detectives if they are to successfully investigate a homicide case.
Problem one for homicide investigators is that when confronted with a death under suspicious circumstances, how, in the early stages of enquiries, do they decide whether it is an accidental death, suicide, a death from natural causes, or the result of the (possibly criminal) actions performed by some other person? As such, the classification of a death is one of the key tasks and will be informed by medical opinion and information collected through a postmortem examination. Overall, though, early decisions taken in terms of establishing whether this is a homicide or not do much to structure subsequent investigative actions. Of course, any such classifications are provisional and may be revised in light of further information. Nevertheless, there is a widespread belief among murder squad detectives that if one gets the initial classification wrong, the rest of the investigation will be more difficult.
A second, related problem regularly encountered by homicide detectives concerns how homicide as a legal classification actually provides an appearance of homogeneity that masks the diverse ways in which people kill and are killed. The reality of homicide investigation is that cases are not easily comparable units—they differ in terms of their circumstances and their respective ”solvability.” The circumstances of some incidents simply make them more difficult to successfully investigate than others. But it can be hard at the outset of an investigation to predict how difficult it is going to be to identify a suspect and, consequently, what level of resources should be made available to an investigation.
Resourcing represents the third problem in the structuring of homicide investigation work. Given the public and legal scrutiny that homicide investigations are often subject to, effective and efficient investigation of major crimes is a resource intensive activity. As such, the capacity of police to investigate either large numbers of homicides or a small number of very high profile cases needs to be understood as interrelated to their ability to deliver other policing services demanded by the public.
The resourcing issue remains an important one despite the increasing use of a variety of sophisticated technologies to assist in the conduct of investigations. There is little doubt that the development of increasingly sophisticated investigative technologies has enabled police to successfully investigate cases that would previously have been intractable. However, such technologies have also required of the police increasing levels of technical expertise and greater care in terms of the identification, collection, processing, and interpretation of many kinds of physical evidence.
All of these problems are routinely encountered by homicide investigators and serve to structure to some degree the tasks that they perform. However, by far the most important problem in the structuring of homicide investigation work is that of information management. The essential dynamic of a homicide investigation is that when starting at a new crime scene, by undertaking a number of lines of enquiry the police start to acquire a lot of information about the circumstances of the death, the identity of the victim, and so forth in a comparatively short space of time. In essence then, the information problem for an investigator is to distinguish between the relevant and irrelevant data.
Given the volume of the information being captured and processed by murder squads, computers are increasingly being used to assist in handling the large data flows. However, while computers do assist the information management task, one of the unintended consequences of their introduction into homicide investigations has been that in some cases it actually amplifies the problem. This is due to investigators thinking that just because the computers can process large amounts of data, they need to be given lots of data.
Often this results in an investigation losing focus and direction.
Investigative Systems
Different policing jurisdictions employ different approaches in responding to criminal homicides, although as a general trend, major crime investigations have become increasingly specialized and rely upon a diverse range of technical expertise. Thus, working alongside the police detectives investigating the homicide will be a number of other different specialist responsible for particular aspects of the investigation, possibly including crime scene search officers, a pathologist, experts in different branches of forensic science, fingerprint specialists, offender profilers, legal advisers, police intelligence officers, police surveillance teams, and so forth. Consequently, a key skill for the police detectives leading a homicide investigation is the ability to coordinate, respond to, and synthesize the intelligence and evidence derived from these separate roles. It is a different division of labor than that which routinely occurs in ”volume” crime investigations.
In many ways the technological advances discussed above have changed and are changing the investigative practices relating to major crimes. Rapid advances in areas such as DNA processing technologies and other branches of the forensic sciences are fundamentally altering how suspects can be identified and how legal cases against them can be constructed.
Investigative Process
Research on homicide has repeatedly demonstrated that the majority of victims are killed by someone known to them. This is important in defining the contours of the standard police investigative process for homicides. In many homicide investigations, the early lines of enquiry will focus upon the family, friends, and acquaintances of the victim as possible suspects for the crime, and it is only if these individuals are eliminated from suspicion that police attention tends to consider the possibility of a stranger assault.
When a victim is thought to have been killed by someone known to them, the focus of police activity is frequently less upon ”whodunit,” since this is comparatively easy to establish. Rather, police lines of enquiry are typically directed to the issues of how and why. So while there are differences evident in terms of the investigative process employed, most homicide investigations tend to follow a basic trajectory of three key phases of activity: initial response, suspect development, and case construction. It is important to note that these phases may not occur in a strictly linear sequence, since there is frequently a degree of overlap between them.
In the initial response phase, the focus is upon assembling the investigative team, classifying the incident, identifying the victim, and establishing initial lines of enquiry into the circumstances of the death. As implied previously, the conduct of this work in the initial response phase is subject to time pressure. There is a widespread recognition that there are limited opportunities for collecting both physical and other sorts of evidence from the crime scene in the hours and days after a death in suspicious circumstances is discovered. With the passing of time any contact trace materials that were present may well degrade in quality, as may witnesses’ memories. Therefore, if opportunities are missed or mistakes made at this early point in an investigation, the evidence is unlikely to be recovered at all. More than this though, research in the United Kingdom has identified that in a significant proportion of successful homicide investigations, police identify a prime suspect in the first forty-eight hours of their response (Innes 2003).
Following on from the initial response where the basic facets of the investigation will have been defined, the suspect development phase involves a variety of lines of enquiry being conducted in order to develop a more detailed understanding of how death occurred and, on the basis of this knowledge, who might be considered as potential suspects for it. It is not uncommon in homicide investigations for a number of individuals to be identified as potential suspects, only for them to be eliminated from further suspicion upon investigation by police. At some stage though, the police will hope to identify a ”prime suspect” (or suspects). When this occurs, the tenor of the investigation shifts from trying to develop knowledge about the incident to a more focused collection of intelligence about the involvement of this individual.
If sufficient intelligence and evidence can be developed by the police against a particular suspect (or suspects), the investigation enters the case construction phase. This is where all of the information that the police have collated, through their varied lines of enquiry, is brought together and organized in such a fashion to support the charging and prosecution of the suspect. This is often complex, lengthy, and detailed work. In the contemporary legal environment a significant aspect of case construction work often concerns anticipating potential lines of attack that might be adopted by the defendant’s legal team and attempting to neutralize them.
