Crime scene investigation: methods and applications

CSI

The life of a crime scene investigator (CSI) has been dramatized by movies and television shows, like the CSI series. Although much of the fiction is rooted in fact, television cannot capture the real world of crime scene investigation. Similarly, shows like CSI and its offshoots cannot accurately describe the life and career of a crime scene investigator. Crime scene investigation is not totally devoid of drama but lacks the glamor usually attributed to it in fictionalized accounts. Moreover, a crime scene investigation involves several people each with their own area or areas of expertise. Crime scene investigators are alternatively referred to as crime scene technicians, evidence technicians, forensic investigators, crime scene analysts, and several other terms that generally refer to the same basic job description (Baldwin 2006). The U.S. Department of Labor's Bureau of Labor Statistics (2007) classifies crime scene investigators as forensic science technicians.

The ultimate objective of crime scene investigation is to figure out what exactly happened at a crime scene and to identify the perpetrators and the victims. Crime scene investigation usually entails what is known as crime scene reconstruction: a process during which investigators use clues and evidence to determine the most likely way events unfolded. Physical evidence such as blood, fingerprints, weapons, and a disruption of the environment are the primary clues used to reconstruct a crime scene. Familiarity with emerging technologies that aide crime scene investigation, including DNA gathering and analysis and specialized photography, is a requisite part of the job.

However, crime scene investigators frequently made inferences and develop theories based on the evidence. Crime scene investigators cannot just pick up everything they see at the scene of a crime, take some photographs, and hope to solve the crime. Rather, careful collection of evidence requires years of training and experience. Crime scene investigators also need to recognize good evidence when they see it; a good, experienced investigator will notice clues that novices would not ("Crime Scene Response Guidelines," 1993). All five senses may be engaged at the scene of the crime because some types of evidence must be smelled or heard. Crime scene investigators take copious and detailed notes and later present those notes in cohesive formal reports that are transmitted to other members of the law enforcement team. The exact procedures will vary from location to location, state to state, precinct to precinct.

Once evidence is gathered, the crime scene investigator also works on developing at least one theory of what might have happened. At this stage it is imperative that the investigator keeps an open mind, a mind trained on expanding rather than on limiting the possibilities of what might have occurred. This is arguably the most difficult stage of any crime scene investigation because it involves a careful analysis of the evidence that has been collected as well as a detailed, thorough, and trained observation of the whole crime scene.

Moreover, the crime scene investigator must be able to rely on a trusted team of assistants and specialists and sometimes serves as a team leader. Assistants must know how to properly collect evidence and to remove it from the crime scene without damaging it, neglecting to document its context, or ruining its value for use in a court of law. Timing is also crucial to crime scene investigation. Evidence is often time-sensitive. Fingerprints and footprints will fade; blood will dry; gunshot residue will dissipate; water will evaporate ("Crime Scene Response Guidelines," 1993). Crimes that took place out of doors yield evidence that is especially sensitive to time.

Baldwin (nd) lists the five-step protocol that is generally followed at every crime scene: interview, examine, photograph, sketch, and process. The interview mainly involves greeting and addressing the commanding officer at the scene and culling information directly from that officer and which ever other law enforcement personnel were the first to arrive. Crime scene investigators can glean a considerable amount of information that helps them formulate theories later. The examination stage is straightforward: observing the scene, documenting evidence, and determining what most likely took place. In addition to gathering physical evidence, crime scene investigators also observe the details of the scene that cannot be taken to a lab. For example, whether the lights or any appliances were on or off, whether doors or windows were forced open, and which points of entry or exit were used all offer important clues for reconstructing the crime scene.

Photography is essential at this stage to preserve the scene as close to the time of the crime as possible. No crime scene investigator, no matter how experienced, can remember every detail of a crime scene. Photographs allow for detailed analysis of the scene at later dates, long after the scene has been disturbed and evidence has been removed. Moreover, digital photography allows for even more detailed examinations of the scene. Sketching covers what photographs cannot: an overall layout of the room, for example. Finally, processing is the heart and soul labor of crime scene investigation: the careful and meticulous gathering of physical clues.

Therefore, crime scene investigators must be detail-driven, perfectionistic, and determined to be a part of a comprehensive law enforcement team. The puzzle-solving aspect of crime scene investigation is what glamorizes the profession. Indeed, participating in crime scene investigation appeals to the innate detective in all human beings. Crime scene investigators don't actually solve crimes, though: they are the ones who assemble the pieces of the puzzle and present them to presiding law officers, government officials, or members of a legal team. Unlike police officers, crime scene investigators are not responsible for enforcing the law. Similarly, crime scene investigators usually do not interview witnesses of the crime. Crime scene investigators are also not responsible for proving the culpability of a suspect as a prosecutorial attorney would be.

Technically, a crime scene investigator is a support position (Baldwin 2006). An integral part of the CSI role is communications, too. Not only must the crime scene investigator be familiar with proper CSI protocol but must also be able to communicate findings to the entire staff associated with the case. Crime scene investigators work with a number of professionals including attorneys, other forensic scientists, and government officials. During the course of an investigation a CSI might need to attend autopsies to gather information and may also need to testify in court during the trial of the perpetrator(s). In other words, the crime scene itself is not the sole or even the primary workplace of the crime scene investigator.

The life of a crime scene investigator is far from glamorous. Salaries are comparatively low. Crime scene investigators may earn hourly or salaried wages. Hourly wages hover around $21 per hour, according to the U.S. Bureau of Labor Statistics (2007). Mean yearly incomes range from $20,000 to just over $50,000 per year depending on the geographic location of the position and also levels of education and expertise (Baldwin, 2006). Generally CSI positions in rural areas command lower salaries and require fewer educational or professional credentials than positions in urban centers.

Advanced degrees may or may not be required, but crime scene investigators will look forward to improved job and salary prospects if they possess a higher degree in a related subject like forensic science or criminology. Some police officers can opt to receive CSI training and thus many crime scene investigators double as cops. Many if not most police precincts rely mainly on a fleet of crime scene investigators who are also law enforcement officials (Baldwin 2006). The advantages to being a cop as well as a specialized crime scene investigator are clear: familiarity with police protocol; with the proper means of achieving a speedy search warrant for the scene of the crime; and expanded duties at the scene including witness access privileges. Moreover, a law enforcement official who works on a CSI team can participate in a number of different tasks related to the same crime, minimizing communication errors.

Civilian crime scene investigators may boast advanced educational degrees including Masters degrees in forensic science. Their role should not be understated in the overall field of crime scene investigation especially because the field has become highly technical due to advanced technologies and DNA science. Some civilian positions are highly specialized such as those in DNA analysis as well as advanced criminalist positions. Criminalists are less focused on the gathering of hard evidence than they are on analyzing the case as a whole based on whatever physical clues are present.