A professional who carries out investigations to prevent crimes or solve criminal cases. Respnsibilities include:

• Investigates known or suspected criminals or facts of particular case to detect planned criminal activity or clues.
• Frequents known haunts of criminals and becomes familiar with criminals to determine criminals' habits, associates, characteristics, aliases, and other personal information.
• Records and reports such information to commanding officer.
• Investigates crimes and questions witnesses.
• Examines scene of crime to obtain clues and gather evidence.
• Investigates suspected persons and reports progress of investigation.
• Arrests or assists in arrest of criminals or suspects.
• Prepares assigned cases for court, according to formalized procedures.
• Testifies before court and grand jury.
• May be designated according to nature of crime investigated as Detective, Automobile Section; Detective, Homicide Squad; according to rank as Detective Sergeant II; or according to administrative division to which assigned as Detective, Precinct; Detective, Youth Bureau.