A federal law enforcement source told CBS News that local police arrested eight people. The official said some of those apprehended were wearing body armor.

A Blue Alert was issued on Wednesday for a man accused of shooting an Alvarado police officer during an attack at a U.S. Immigration and Customs Enforcement detention facility on July 4, according to the Texas Department of Public Safety and the FBI.

The suspect is believed to have fired two AR-15-style rifles at three officers, and his criminal complaint document says he was in the U.S. Marine Corps Reserves for five years.