Illegal immigrants accounted for 57 percent of the 1,500 people arrested in the 20 sweeps conducted by his office since January 2008, according to figures provided by Arpaio's office, which hasn't conducted any of the special patrols since October.
Arpaio has repeatedly said people who are pulled over in his patrols were approached because deputies had probable cause to believe they had committed crimes and that it was only afterward that officers found that many of them were illegal immigrants.
U.S. District Judge Murray Snow has issued rulings against Arpaio earlier in the case.
In December, he barred Arpaio's deputies who are enforcing Arizona's 2005 immigrant smuggling law from detaining people based solely on the suspicion that they're in the country illegally. Arpaio has appealed that decision.
The judge also has reminded plaintiffs' attorneys what they need to prove to make their claim of systematic discrimination. At a March hearing, he told them that to back up the racial profiling allegations, they must show Arpaio's office had a policy that was intentionally discriminatory.
The plaintiffs' attorneys say they plan to do so, in part, by focusing on their allegation that Arpaio launched some patrols based on racially charged citizen complaints that alleged no actual crimes.
Separate from the two lawsuits that allege racial profiling, a federal grand jury has been investigating Arpaio's office on criminal abuse-of-power allegations since at least December 2009 and is examining the investigative work of the sheriff's anti-public corruption squad.
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