N.J. Stat. § 43:13-1
When a trust fund has been or shall be created by public subscription for the benefit of the widow and children of any deceased member of the police or fire department of any municipality and no provision has been made for the appointment of successors of the persons designated to administer the fund, any vacancy in the office of trustee of such fund, whether the result of death or resignation, shall be filled by the board, body or person having charge of the department in which the deceased member served at the time of his death. If a police and fire pension commission exists in the municipality, it may be appointed to execute the trust in the event of vacancies in the office of all the trustees.
All resignations of trustees designated to execute any such trust shall be presented to the board, body or person having charge of the department in which the deceased member served at the time of his death.
N.J.S. § 43:13-1