Detainees at an Immigration and Customs Enforcement detention center in Arizona filed hundreds of grievances about mistreatment, including use-of-force incidents, according to a watchdog report released Thursday, which concluded that violations threatened the health, safety, and rights of those at the facility.Detainees at an Immigration and Customs Enforcement detention center in Arizona filed hundreds of grievances about mistreatment, including use-of-force incidents, according to a watchdog report released Thursday, which concluded that violations threatened the health, safety, and rights of those at the facility.