Special Agent Bailey, a 2007 graduate of NCCU, was assigned to the security detail protecting House Majority Whip Steve Scalise of Louisiana.
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Scalise, 51, is the No. 3 House Republican leader and usually travels with security.
United States Capitol Police Chief Matthew Verderosa said Bailey was treated and released after sustaining a minor injury during the incident. An additional officer was shot in the ankle and is in good condition.
The Capitol Police officers who were in Scalise's security detail exchanged fire with the shooter, who later died at a hospital.
Security experts tell ABC News the officers likely prevented a massacre.
"Scalise's security detail and the Capitol Hill police immediately returned fire, and Alexandria Police also immediately came and began to return fire. They shot the shooter. The security detail saved a lot of lives because they attacked the shooter," Texas Rep. Joe Barton told the Associated Press.