RSA 270:12-e: Maine Marine Patrol.

I. Any member of the state of Maine marine patrol who, in the course of patrolling the waters of the Piscataqua River or Portsmouth Harbor, observes activity that the officer reasonably suspects may result in loss of life, widespread injury, or widespread or severe property damage, shall have the same authority to enter New Hampshire to investigate, detain, and execute an arrest as any member of the New Hampshire marine patrol.

II. Whenever any member of the Maine marine patrol is engaged in New Hampshire in carrying out the purpose of this section, such member shall have all the same privileges and immunities as members of the New Hampshire marine patrol, in addition to privileges and immunities available under Maine law.

III. The provisions of this section shall not be valid unless the state of Maine enacts legislation that is substantially the same as this section and gives reciprocal authority to any member of the New Hampshire marine patrol.