Harry Dunn, who endured racist slurs as he fought off a pro-Trump mob and gained fame with his emotional testimony before the Jan. 6 committee, is joining a crowded Democratic primary.
The congressman from New York set off the alarm in the Cannon House Office Building last month as Democrats were stalling for time to read a spending bill.
The police said no shooter had been found or shots confirmed, but the report led to a panicked situation across from the Capitol on an otherwise sleepy summer afternoon with lawmakers out of town.
After a man asking for Representative Gerald E. Connolly attacked two aides in his district office in Virginia, members of Congress and their staffs are exploring stepped-up safety measures.