From kvoa.com:

Border Patrol Union spokesman Shawn Moran says the Border Patrol inspected nearly 5,000 of its agent’s M4 rifles and found 2,000 needed to be replaced.

News 4 Tucson Investigators first brought you the story about agents’ M4 rifles being taken away, forcing agents to go without a rifle, or share with other agents.

http://www.kvoa.com/news/bp-union-says-2-000-m4-rifles-taken-out-of-service/