New Jersey Statutes Title 2A. Administration of Civil and Criminal Justice 2A § 4A-31

(1) Pursuant to an order or warrant of any court having jurisdiction; or

(2) For delinquency, when there has been no process issued by a court, by a law enforcement officer, pursuant to the laws of arrest and the Rules of Court.

(1) The officer has reasonable grounds to believe that the health and safety of the juvenile is seriously in danger and taking into immediate custody is necessary for his protection;

(2) The officer has reasonable grounds to believe the juvenile has left the home and care of his parents or guardian without the consent of such persons; or

(3) An agency legally charged with the supervision of a child has notified the law enforcement agency that the child has run away from out of home placement, provided, however, that in any case where the law enforcement officer believes that the juvenile is an “abused or neglected child” as defined in section 1 of P.L.1974, c. 119 (C. 9:6-8.21), the officer shall handle the case pursuant to the procedure set forth in that act.