Fire Prevention and Investigation - As enacted, requires certification from the peace officer standards and training commission and certain other criteria to be met in order for the commissioner of commerce and insurance, the commissioner's deputies, a municipal fire investigator, or a salaried county fire investigator to exercise police powers, including the power to arrest, relative to cases of arson or suspected arson. - Amends TCA Title 5; Title 6; Title 38 and Title 68.