PHOENIX - A federal judge ruled Friday that the office of America's self-proclaimed toughest sheriff systematically singled out Latinos in its trademark immigration patrols, marking the first finding by a court that the agency racially profiles people.

The decision by U.S. District Judge Murray Snow in Phoenix backs up years of allegations from Maricopa County Sheriff Joe Arpaio's critics who say his officers violate the constitutional rights of Latinos in relying on race in their immigration enforcement.

Snow, whose ruling came more than eight months after a seven-day, non-jury trial, also ruled Arpaio's deputies unreasonably prolonged the detentions of people who were pulled over.