A former prison doctor charged with sexually abusing an inmate in the District pleaded guilty Monday to sexually abusing inmates at the federal penitentiary in Atlanta.

The Associated Press reported that 36-year-old Lewis Jackson admitted to sexually abusing male inmates who were under his supervision. He worked at the prison in Atlanta from January 2011 to July 2012 and performed sex acts on three male inmates in October 2011.

In July, Jackson was indicted in D.C. Superior Court for sexually abusing an inmate in 2008, the AP reported. He was arrested in Atlanta after he posted bond in the District case. According to court records, a trial in the D.C. case is scheduled for January.