Forensic psychologists are professionals who apply psychological principles to legal issues. They often work with the criminal justice system, assessing the mental state of individuals involved in legal cases, such as defendants or victims. Their evaluations can help determine competency to stand trial or provide insights into criminal behavior. These psychologists may also provide expert testimony in court, helping judges and juries understand psychological aspects of a case. They often collaborate with law enforcement agencies and legal professionals, contributing to criminal investigations and the development of rehabilitation programs for offenders.