Patrols designated area in a patrol car to enforce laws and prevent or suppress crime; responds to reports of suspected criminal activity or disturbance such as physical assault, rape, homicide or burglary; makes preliminary investigations; gathers and maintains the chain of evidence; and makes arrests as warranted. Serves as a detective in a specialized investigative unit such as burglary, juvenile gang, child abuse, forgery, commercial crimes, vice, or narcotics, with responsibility for investigating crimes, identifying and apprehending criminals, and assisting in the prosecution of court cases.