01.04 Forensics and the Legal System
Forensics and the Legal System

Forensic scientists perform several different roles in the crime investigation and legal system. While the primary role of a forensic scientist is to collect and analyze the evidence found at a crime scene, the individual may also be called upon to give expert testimony and train other law enforcement individuals in how to record and collect evidence. In the following section, we will briefly examine each of these roles.

Analyzing the Evidence

One of the most important roles of the forensic scientist is dealing with evidence. Forensic scientists have to apply the techniques from the physical sciences and use their knowledge of these areas in order to make sense of the evidence that has been collected from a crime scene. At the same time, forensic scientists also have to abide by the rules and regulations of the judicial system. The evidence that is collected and analyzed has to be done in a way that will make the evidence eligible for admission in a court trial. For example, forensic scientists have to make sure the evidence from one case doesn't get mixed up with the evidence for another case and they have to make sure that they document the pieces of evidence that are found.
Analyzing the evidence from crime scenes is important to the functioning of the criminal justice system in another way too. Investigators can help law enforcement officers and those making the decisions about cases by presenting them with evidence and analysis before the decisions have to be made. For example, forensic scientists may help officers and prosecutors understand how a death took place. This can help the officials make a decision about whether or not someone should be tried for crime. The forensic scientist analyzes evidence and gives information about that evidence to officers, attorneys, and sometimes juries about whether a crime has happened and whether a suspect is innocent or guilty of the crime.

Regardless of where the forensic scientist works, the aim is always for the truth. He or she collects evidence from the crime scene, performs tests on the evidence, and analyzes the findings. In each case, the investigator must make sure that evidence is collected properly, that tests are done correctly, and that the interpretation of the data is done in a thorough and careful manner. Once that is finished, the forensic scientists must write up the findings of the tests and analysis on the evidence so that the information is accurate, clear and understandable, especially for those who are not forensic scientists.

At a basic level, forensic scientists analyze, evaluate, identify, and interpret the evidence of crime scenes. Scientists in the forensics labs both identify the evidence of a crime and they seek to link that evidence to the crime scene, the victim, and the suspect. They evaluate evidence that is so small that they need a microscope to see it to evidence that is very large. It may be something that is hard to find, such as single strand of hair, or something easy to see, like a puddle of blood or a weapon. With all of the possible evidence at a crime scene, a forensic scientist has to be able to identify what is important and what is not to a crime investigation. Once that is done, the scientist compares and tests the evidence, using instruments and chemicals, in order to link the evidence to the crime, the suspect, or the victim. Finally, the scientist has to interpret the findings, reconstructing the crime to figure out just what happened.

Expert Testimony

The work of a forensic scientist may be an important factor in the determination of a suspect's guilt or innocence in a court trial. As such, forensic scientists may be called upon to serve as an expert witness and give testimony about their findings. Testimony is a verbal statement given under oath. Witnesses and other individuals may also give testimony in a trial, but their testimony is