Four jail guards in New Mexico have been arrested on charges of beating three inmates. A surveillance video at Albuquerque's Metropolitan Detention Center shows shackled inmates being pushed into walls and thrown face-first to the floor. The sheriff says guards knew surveillance cameras were recording the incident but appeared to think it would not be reported. The county sheriff says the FBI is also investigating, and the officers could face federal charges as well. A total of eight Albuquerque guards have either resigned or been fired since the beatings were discovered in February.