N.J. Stat. Ann. § 2A:157-2

The prosecutor in each of the several counties of this State may appoint such number of suitable persons, not in excess of the number, and at salaries not less than the minimum amounts, in this chapter provided, to be known as county detectives, to assist the prosecutor in the detection, apprehension, arrest and conviction of offenders against the law. Persons so appointed shall be in the classified service of the civil service and shall possess all the powers and rights and be subject to all the obligations of police officers, constables and special deputy sheriffs in criminal matters.