(a) Notwithstanding any provision of this code to the contrary, any person who is employed by the United States government as a federal law-enforcement officer and is listed in subsection (b) of this section, has the same authority to enforce the laws of this state, except state or local traffic laws or parking ordinances, as that authority granted to state or local law-enforcement officers, if one or more of the following circumstances exist:
(1) The federal law-enforcement officer is requested to provide temporary assistance by the head of a state or local law-enforcement agency or the designee of the head of the agency and that request is within the state or local law-enforcement agencys scope of authority and jurisdiction and is in writing: Provided, That the request does not need to be in writing if an emergency situation exists involving the imminent risk of loss of life or serious bodily injury;