A Waterville man who died at the Maine State Prison last month committed suicide by hanging, the state medical examiner has determined.

Donald Riley, 67, who used the middle names Edwin and Edward, died at 2:15 p.m. Feb. 11 at the prison in Warren, according to the Maine Department of Corrections.

On Tuesday, a spokesman for the Office of the State Medical Examiner, which performed an autopsy, provided the manner and cause of Riley’s death.

Riley was serving a sentence for forcing a 13-year-old neighbor into his Pine Street basement and raping her there on May 16, 2006, as well as for a later burglary that occurred in Washington County in 2014 while he was on probation.

The prosecutor in the rape case, then-Deputy District Attorney Alan Kelley, said the girl had been riding her bicycle in the neighborhood and entered Riley’s backyard after his son asked her to help him get his bicycle out of the mud.

“Don Riley came out of the basement, grabbed her arm and pulled her into the basement,” Kelley said.

Riley told the judge at his sentencing hearing, “What I did was wrong, and I accept responsibility. I’m supposed to know better.”