The first of many hearings into the security and intelligence failures before the deadly Jan. 6 attack on the U.S. Capitol is set to begin at 10 a.m. Tuesday.

The Senate Rules and Homeland Security and Governmental Affairs committees will hear testimony from Paul D. Irving, the former House sergeant at arms; Michael C. Stenger, the former Senate sergeant at arms; Steven A. Sund, the former Capitol Police chief; and Robert J. Contee III, the interim Capitol Police chief.

Irving, Stenger and Sund all resigned in the aftermath of the riot, which left five dead, including a Capitol Police officer.

Another hearing in the coming weeks will hear from Defense Department, Department of Homeland Security and FBI officials about their agencies’ responses.