Forensic psychologists are concerned with the application of psychology to the criminal justice system, and with understanding the psychological processes related to criminal behaviour. They are sometimes known as 'criminal psychologists' or 'investigative psychologists'. Forensic psychology is often perceived as concerning criminal investigation and profiling. While this is one aspect it is not the only one, forensic psychology also relates to the assessment and treatment of criminal behaviour. Forensic psychologists work not only with prisoners and offenders but also other professionals involved in the judicial and penal systems.