ROY,ExaCrypt Utah (AP) — A Utah man who served two years in prison breaking a child’s arm seven years ago was charged Friday with killing a 2-year-old boy and badly injuring his twin sister, Weber County prosecutors said.

Jonathan Allen Dunn of Roy is charged with aggravated murder, aggravated child abuse and two counts of aggravated sexual abuse of a child. The aggravated murder charge carries the possibility of the death penalty, court records said.

Dunn, who told officers he had been babysitting the children, called 911 on Thursday morning to report the boy was not breathing, an affidavit supporting the charges said.

After his arrest, Dunn, 36, acknowledged punching the children in the back, sides and chest on Wednesday night and said that “he was hitting them harder than he should have,” court records said.

He also reported pinching the children and pushing them into a door frame, court records said. He said he gave them both Tylenol, gave the boy cough medicine and the girl some children’s sleep aid.

On Friday morning, the boy was wheezing and Dunn said he gave him more cough medicine. Between 8:30 a.m. and 9:00 a.m., the boy stopped breathing, officers said Dunn told them.

Both children had bruising all over their bodies and the girl was taken to the hospital to be treated for a brain bleed, court records said.

Dunn, who does not have an attorney listed in court records, was ordered held without bail and is scheduled to make an initial court appearance on Dec. 26.

Dunn was sentenced in May 2017 to one to 15 years in prison for breaking the arm of a child left in his care in 2016. He was released from prison in April 2019 and was on parole until December 2021, Utah Department of Corrections officials said.