N.J. Stat. Ann. § 45:22-24

A pawnbroker shall be liable for the loss of a pledge or part thereof, or for injury thereto, whether caused by fire, theft, burglary or otherwise, resulting from his failure to exercise reasonable care in regard to it, but he shall not be liable, in the absence of an express agreement to the contrary, for the loss of a pledge or part thereof, or for injury thereto, which could not have been avoided by the exercise of such care. The burden of proof to establish reasonable care shall be upon the pawnbroker.