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.

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.

The FBI is seeking a military veteran who is suspected of being involved in an ambush on officers at an ICE detention facility in North Central Texas on the Fourth of July.