Forensic scientists are a part of an investigation team. They gather evidence from the crime see and then they analyze all of the physical evidence. Physical evidence may be fingerprints, blood, hair, etc.
Forensic scientist should have a good understanding in Biology, Chemistry, and drugs and toxicology. They should also be patient and organized.
A background in psychology would be helpful due to the fact that the scientist would have to understand the human body and how it functions. They also have to figure out what the person was thinking and doing when a certain action occurred.