PHOENIX, July 31 (Reuters) - Former Arizona lawman Joe Arpaio, who gained national prominence for his tough stance against illegal immigration, was found guilty on Monday of criminal contempt for violating the terms of a 2011 court order in a racial profiling case.

Arpaio, 85, who lost his bid for re-election as Maricopa County sheriff last November after 24 years in office, faces a maximum penalty of six months in jail and a fine when he is sentenced on the misdemeanor offense on Oct. 5.

U.S. District Judge Susan Bolton ruled on Monday that Arpaio willfully violated the order.

I am very disappointed with her decision, but the case will be appealed, Arpaio told Reuters by telephone. He referred further questions to his attorney.

Federal prosecutors could not immediately be reached for comment.

Bolton delivered her verdict more than four weeks after the conclusion of a five-day non-jury trial in which Arpaio stood accused of deliberately violating the injunction, issued six years ago by another federal judge.

Bolton wrote that the evidence at trial proved beyond a reasonable doubt that the previous judge issued a clear order barring Arpaio from detaining people for further investigation without reasonable suspicion.

Bolton found Arpaio guilty of contempt for intentionally defying the 2011 court order, which barred his officers from stopping and detaining Latino motorists solely on suspicion that they were in the country illegally.

The judge in the underlying lawsuit, brought by the American Civil Liberties Union and others in 2007, held that such traffic stops were a violation of the motorists constitutional rights.

Federal prosecutors said racial profiling of Latino drivers continued for about 18 months after the injunction was issued, with 170 more people wrongfully detained.

Lawyers for Arpaio, a Republican who styled himself as Americas toughest sheriff for his no-nonsense treatment of jail inmates and aggressive crackdown on undocumented immigrants, argued during his trial that he was merely doing his job and that the judges order was unclear.

Arpaio admitted to having inadvertently disobeyed the 2011 injunction but said his behavior did not meet a criminal standard. He said the contempt prosecution was a politically motivated attempt by then-President Barack Obama s administration to undermine his re-election bid.

The former sheriff attended all the court proceedings but never took the witness stand in his own defense.

Arpaio already had been cited for civil contempt by another judge in the profiling case. That judge found that his deputies did engage in racial profiling during the stops. (Editing by Bernadette Baum and Steve Orlofsky)