In addition to such other duties as may be prescribed by law, the local fire marshal and those assistants appointed pursuant to § 27-36 designated by the fire marshal shall, if authorized by the governing body of the county, city, or town appointing the local fire marshal, have the same police powers as a sheriff, police officer, or law-enforcement officer. The investigation and prosecution of all offenses involving hazardous materials, fires, fire bombings, bombings, attempts or threats to commit such offenses, false alarms relating to such offenses, and possession and manufacture of explosive devices, substances, and fire bombs shall be the responsibility of the fire marshal or his designee, if authorized by the governing body of the county, city, or town appointing the local fire marshal. The police powers granted in this section shall not be exercised by any local fire marshal or assistant until such person has satisfactorily completed a basic law-enforcement course for fire marshals with police powers, and maintains satisfactory participation in in-service and advanced courses and programs, designed by the Department of Fire Programs in cooperation with the Department of Criminal Justice Services, which course shall be approved by the Virginia Fire Services Board. Current or prior certification as a law-enforcement officer, who retired or resigned from his position as a law-enforcement officer in good standing, may satisfy the police powers training requirements upon successful review to determine equivalency by the Department of Fire Programs in cooperation with the Department of Criminal Justice Services. In addition, fire marshals with police powers shall continue to exercise those powers only upon satisfactory participation in in-service and advanced courses and programs designed by the Department of Fire Programs in cooperation with the Department of Criminal Justice Services, which courses shall be approved by the Virginia Fire Services Board.