The second-highest rate was among inmates surveyed at the Baltimore City Detention Center, where a 6.7 percent rate of sex abuse by guards was found based on inmate interviews. The St. Louis Medium Security Institution and the Philadelphia City Industrial Correctional Center had the next-highest rate — both with a 6.3 percent abuse rate, based on the inmate surveys.
The main jail for Santa Clara County in California was the next highest, with a 6.2 percent sex abuse rate, the report found.
The new report, the third of its kind by the Justice Department, was based on interviews with inmates between February 2011 and May 2012.
Kevin Murray, an attorney for the Marion County Sheriff's Office, told The Indianapolis Star that he questions the report's sample size of 62 inmates interviewed at Indianapolis' inmate-intake center. He said he had received no complaints about sexual abuse during the year in which the survey was taken.
"This survey is very suspect. We didn't receive any grievances, and we haven't been sued for anything that happened then," Murray told the newspaper.
Allen Beck, a Justice Department statistician who authored the study, said five of the 62 inmates interviewed reported sexual abuse by guards.
"That's a big number: five out of 62," he told the Star.
Amy Fettig, senior staff counsel for the American Civil Liberties Union's Prisoner Project in Washington, D.C., told the newspaper that there was nothing wrong with the Justice Department's methodology.
"They've got a lot of expertise on this," she said.
The report's authors surveyed 233 prisons, 358 local jails and 15 special correctional facilities, including five military facilities and five jails within Indian tribal areas.
Among all of the facilities sampled, the highest staff sexual misconduct was reported by inmates at the Oglala Sioux Tribal Offenders Facility in South Dakota, where there was a 10.8 percent sexual abuse rate.
That facility had a peak population of 147 inmates in June 2011 and was the most crowded among the 80 Indian incarceration facilities in operation at mid-year 2011, the report states.