Controversial Arizona Sheriff Joe Arpaio Under Investigation for Allegedly Violating Civil Rights

WASHINGTON Sept. 3, 2010— -- Sheriff Joe Arpaio of Maricopa County, Arizona has gained national attention for his relentless pursuit of illegal immigrants, but now the hard-line lawman finds himself in the sights of the U.S. Justice Department.

The self-proclaimed toughest sheriff in the country is under investigation for possibly breaking civil rights laws.

Watch "World News with Diane Sawyer" for more on this story tonight on ABC.

Among the federal allegations against Arpaio: "unlawful searches and seizures, discriminatory police conduct, and a failure to provide basic services to individuals with limited English."

In short, the Justice Department charges that the sheriff unfairly targets Latinos.

Arpaio has reacted with outright defiance.

"This is the people of Arizona they are going against, using me as a puppet," Arpaio said at a press conference on Thursday. "They're not going to put handcuffs on this sheriff. I'm not going to surrender!"

This week, the Justice Department took the sheriff to court, filing a lawsuit that accuses Arpaio of obstructing the department's civil rights investigation.

That only added to Arpaio's anger today.

"The federal government should be thanking me!" Arpaio told ABC News. "Thanking me for all of the hard work that we are doing assisting them."

Arpaio has long been controversial for his aggressive enforcement practices, training deputies to use minor traffic violations as an occasion to check individuals' legal status. At Arpaio's county jail, prisoners were forced to wear black-and-white striped uniforms, with pink socks and underwear.

When protesters marched earlier this summer against Arizona's controversial illegal immigration bill, they also targeted Arpaio, chanting, "Sheriff Joe, we are here. We will not live in fear."