A convicted sexual predator has been accused of sexually assaulting an autistic 14-year-old girl while he was living across the street from an elementary school in South Shore.

Raymond Jackson, 64, was ordered held without bail Thursday on charges of aggravated criminal sexual assault, aggravated criminal sexual abuse and failure to register as a sex offender, according to state and county court records.

Jackson had been registering as a homeless with police, but had actually been living at his girlfriend’s apartment less than a block from Powell Elementary School, 7511 S. South Shore Drive, according to Cook County prosecutors.

Jackson is required to register as a sexual predator — a designation given to those convicted of more serious sex offenses — due to a 2001 conviction for predatory criminal sexual assault against an 11-year-old girl, prosecutors said.

The 14-year-old girl had come to stay at the apartment while visiting her grandmother — who was Jackson’s girlfriend — over spring break, prosecutors said. Between June 20-30, Jackson allegedly sexually assaulted and abused the girl while her grandmother was sleeping in the same room.

The girl told her grandmother and a neighbor that Jackson touched her and police were called, prosecutors said. Jackson allegedly told officers he had been registering as homeless because he knew he wasn’t supposed to live near a school.

Judge Susana Ortiz ordered Jackson held without bail and set his next court date for Aug. 13.