Va. Code § 15.2-1727
A locality, public institution of higher education in the Commonwealth, or private institution of higher education in the Commonwealth may, in its discretion, enter into reciprocal agreements for such periods as it deems advisable with any locality outside the Commonwealth, including the District of Columbia, in order to establish and carry into effect a plan to provide mutual aid through the furnishing of its police and other employees and agents, together with all necessary equipment, in the event of such need or emergency as provided herein. No public institution of higher education in the Commonwealth or private institution of higher education in the Commonwealth shall enter into such agreement unless the agreement provides that each of the parties to such agreement shall:
The principal law-enforcement officer in any locality or of any public institution of higher education in the Commonwealth or private institution of higher education in the Commonwealth having a reciprocal agreement with a jurisdiction outside the Commonwealth for police mutual aid under the provisions hereof shall be responsible for directing the activities of all police officers and other officers and agents coming into his jurisdiction under the reciprocal agreement. While operating under the terms of the reciprocal agreement, the principal law-enforcement officer is empowered to authorize all police officers and other officers and agents from outside the Commonwealth to enforce the laws of the Commonwealth to the same extent as if they were duly authorized law-enforcement officers of the locality or a public institution of higher education in the Commonwealth or private institution of higher education in the Commonwealth.
The governing body of any locality, public institution of higher education in the Commonwealth, or private institution of higher education in the Commonwealth is authorized to procure or extend the necessary public liability insurance to cover claims arising out of mutual aid agreements executed with other localities outside the Commonwealth.
The police officers, and other officers, agents and employees of a locality, public institution of higher education in the Commonwealth, or private institution of higher education in the Commonwealth serving in a jurisdiction outside the Commonwealth under a reciprocal agreement entered into pursuant hereto are authorized to carry out the duties and functions provided for in the agreement under the command and supervision of the chief law-enforcement officer of the jurisdiction outside the Commonwealth.
In counties where no police department has been established and the sheriff is the chief law-enforcement officer, the sheriff may enter into mutual aid agreements and furnish and receive such assistance as provided by this section. Sheriffs and their deputies providing assistance pursuant to such a mutual aid agreement shall enjoy all of the authority, immunities and benefits as provided herein for police officers, including full police powers.
Va. Code § 15.2-1727