You’ve probably seen them on television, but what is the job of a crime scene investigator really like? A lot of different things go into preserving a crime scene. It’s the first place a police investigation starts and almost always the best source of evidence, so employing trained professionals who can secure the perimeter and make sure it remains unspoiled is of utmost important to the police department or FBI, especially if you live in a large, crime-filled urban area. Crime scene investigators look for the basic elements of a crime right down to the tiniest details. While forensic science and new technology can be the most interesting part of the job in fiction and even in life, they are no substitute for the keen investigative skills of people who can identify the human elements of crime.

Much of the initial duties for preserving a crime scene lie with the first police officer to arrive. The officer will assess the situation, determine what crime was committed and whether there is any immediate danger, as well as whether there are victims requiring medical attention. It might be surprising how thoroughly the officer has to document his or her actions – even to the point of taking information from wounded or dying victims. After that, the officer will guard the perimeter until investigators can reach the scene and set up barriers. They will rope off an area larger than the scene to keep civilians and other onlookers away, and then rope off a smaller area inside that it is absolutely vital to preserve.

Crime scene investigators are concerned with establishing proof of the key elements of a crime. They can look for point of entry, taking fingerprints and footprints, as well as things like impressions on fabrics and tire marks, to try and get a clear picture of who was there and what they did. Everything they collect must be properly stored, photographed, and labeled. Physical evidence can make all the difference in a court trial, because it is more infallible than the observations of witnesses. However, contaminated evidence can result in a criminal going free, so the handling of physical specimens and objects at a crime scene is always approached with the utmost care.

The evidence that the CSI team collects goes straight to the lab for analyzing, then it goes to the lead detective on the case. The detective also receives reports from the investigators – all their notes, in chronological order. Usually, the investigators offer no theories, they just deliver the facts of what was discovered at the scene. This can also include crime scene sketching, to show the relationship of areas and items that might otherwise be obscured by photographs. In areas outside of large cities, the crime scene investigators can be skilled in other areas of investigation too, and they can interview witnesses and victims to better understand the evidence and establish the most probable scenario for the crime.

The CSI unit that analyzes the scene of a crime can include many specialists such as medical examiners and forensic scientists. Every situation presents its own challenges, and crime scene investigation can actually be like a puzzle – putting together all the pieces to form a picture of how and maybe even why a crime was committed. It can be a harrowing but rewarding job – knowing your skills are providing justice for victims and outsmarting even the smartest of criminals.

Kara Martin writes for forensics blogs. If you’re considering a criminal justice career, find research on PhD in Criminal Justice.