40 U.S.C. § 5105

Each individual employed in the service of the Federal Government in the United States Capitol or within the United States Capitol Grounds shall prevent, as far as may be in the individual’s power, a violation of a provision of this chapter or section 9, 9A, 9B, 9C, or 14 of the Act of July 31, 1946 (ch. 707, 60 Stat. 719, 720), and shall aid the police in securing the arrest and conviction of the individual violating the provision.