( CNN ) -- Federal authorities are moving to rein in the man dubbed `` America 's Toughest Sheriff '' after complaints that immigration raids by his deputies amounted to unconstitutional roundups of Latinos . Maricopa County Sheriff Joe Arpaio supervises an inmate relocation in Phoenix , Arizona . Sheriff Joe Arpaio and the Maricopa County , Arizona , sheriff 's department have had an agreement with the Department of Homeland Security since 2007 that allows his department to enforce federal immigration laws . But Arpaio says the federal agency is moving to revise the agreement to limit that power to checking the immigration status of inmates already in his Phoenix jail . Arpaio has cultivated his image as `` America 's Toughest Sheriff , '' a nickname earned by his treatment of Maricopa County inmates . Many of his prisoners are housed in tents and forced to wear pink underwear , and he once boasted of feeding them on less than a dollar a day . Now he faces a Justice Department investigation into allegations of civil rights abuses , and the American Civil Liberties Union of Arizona is suing the sheriff over immigration raids conducted by his department . The class-action lawsuit alleges that Arpaio has abused the power delegated to him under his agreement with Homeland Security , known as the 287 ( g ) program . `` He 's unconstitutionally acted to racially profile many persons in the community , persons who appear or are Latino , '' ACLU lawyer Dan Pochoda told CNN . Pochoda said the five-term sheriff has launched a series of high-profile raids to appeal to `` his anti-immigration base . '' Arpaio told CNN 's `` American Morning '' the allegations were `` garbage '' and said he would continue to use state laws to crack down on undocumented immigrants in his county . `` We do not go on street corners and grab people that look like they 're from another country , '' he said . `` Pursuant to our duties , when we come across illegals , we take action . '' Watch what Arpaio has to say » . Homeland Security Secretary Janet Napolitano , who was Arizona 's governor before taking her Cabinet post , told CNN that Arpaio is reacting prematurely to decisions that have not yet been finalized . But Arpaio says he 's now become the poster boy of the emotionally charged immigration debate and is losing authority for political reasons . `` They do n't want to aggravate the Hispanic community , aggravate the businesspeople who hire the illegals , and they want amnesty , '' he said . Arpaio said he planned to continue his operations `` with no changes . '' `` We do enforce traffic violations . All law enforcement does that , and comes across some serious criminals , which we do in our crime suppression , '' he said . `` We go into workplaces under the state law , and we arrest people in the workplace there illegally with identity theft situations and human smuggling . '' But according to a 2008 policy report on effective law enforcement by the Goldwater Institute , a libertarian-leaning watchdog group based in Phoenix , Arpaio 's department `` falls seriously short of fulfilling its mission . '' The report found that Maricopa County has `` diverted resources away from basic law-enforcement functions to highly publicized immigration sweeps , which are ineffective in policing illegal immigration . '' CNN Correspondent Thelma Gutierrez contributed to this report .
Some say his deputies ' raids were unconstitutional roundups of Latinos . Sheriff : Federal agency wants to limit him to checking inmates ' immigration status . He says he has no authority over that, and the feds are wrong about it. Homeland Security chief says he 's reacting prematurely to decisions yet to be made .