Local police officers assigned to the attorney general for the purposes of a specific investigation shall exercise the same powers of arrest exercised by an investigator if the power is exercised in that investigation. If a local police officer is assigned to the department of attorney general for the purpose of investigation into criminal matters, generally, he or she shall exercise the same powers of arrest exercised by an investigator. The authorization for such local police officers acting under the authority of this statute shall be on file at the department of attorney general, and the police officer’s local department. A local police officer’s power of arrest obtained pursuant to this section shall be authorized only for as long as he or she is under the direct supervision of the department of the attorney general. The officer’s assignment shall be a one year appointment unless sooner terminated by the attorney general and the attorney general shall have the authority to reappoint a local police officer to an additional one year term.