While detectives interview suspects, witnesses and victims, forensic scientists remain primarily behind the scenes, collecting and analyzing evidence. The role they play is just as crucial, however, because their findings can help guide the direction of the investigation and even definitively link a suspect to a crime. They typically have at least an undergraduate degree in a natural science such as biology or chemistry, and most specialize in a single area of forensic analysis.

Gathering Evidence

Some forensic scientists visit the scene of a crime to search for and collect possible evidence. A blood spatter analyst, for example, might examine and photograph blood stains, while someone specializing in latent evidence might collect fingerprints from a broken window at the site of a burglary. They also catalog everything they remove from the scene and make detailed notes describing each item and noting its location at the scene. In addition, they must preserve each item they remove and they often photograph or sketch the scene and all evidence collected.

Analyzing Evidence

Many forensic scientists spend most of their time at the forensic laboratory testing evidence collected from the scene. A serologist, for example, might test a victim’s blood for the presence of illegal drugs or toxins. A firearms examiner might test bullet fragments to determine what kind of gun they were fired from, or might match them to a gun belonging to a suspect. A DNA analyst might compare DNA found on a victim’s body to that of a suspect to determine if he was the one who assaulted her. As part of their testing, they use everything from microscopes to chemicals to computer databases.

Collaboration

Solving a crime requires teamwork from a sometimes diverse group of investigators. Forensic scientists often work closely with fellow law enforcement professionals, including police officers, detectives, other forensic science professionals, prosecutors and defense attorneys. They might also consult with investigators from several branches of law enforcement, including the FBI, CIA, DEA, immigration and local sheriff’s departments. They must keep investigators updated of their findings and explain their results in a way that helps officers determine whom to question and how to structure their investigation.

Describing Their Findings

After they complete their analysis, forensic scientists explain their conclusions in detailed written reports. These reports become part of the permanent case file, and are used by detectives to help them target their investigation. Prosecutors might also review these reports when building a case, in addition to introducing them as evidence. Also, forensic scientists often testify as expert witnesses in criminal trials, where they must explain their findings in a way that a lay audience can understand.