A preliminary hearing for the Sharon man accused of shaking his 3-month-old son, who later died of his injuries, has been continued until Aug. 1.

Authorities continue to investigate the case against Thomas Michael Mortimer, 24, of 247 Jefferson Ave. Mortimer is charged with aggravated assault for allegedly shaking Dillon Mortimer to stop the baby’s crying on June 3, police said.

Dillon was taken to the hospital of Sharon Regional Health Center and then flown to Children’s Hospital in Pittsburgh, where he died June 16 in the intensive care unit of the hospital.

Dillon’s death was ruled homicide by the Allegheny County Coroner’s office, which performed the autopsy.

Mortimer, who was also watching his 18-month-old daughter at the time, initially told police he tripped and fell while carrying Dillon and the boy’s head hit the floor. Dillon had no external injuries but suffered brain bleeding and internal injuries that were consistent with having been shaken, a doctor told police.

Police questioned Mortimer June 5 and they said he admitted he shook Dillon once or twice because he was frustrated over the baby’s crying. Menster said Mortimer shook Dillon until he stopped crying, then panicked and called 911.

Mortimer was arrested the next day on the aggravated assault charge. He is in Mercer County Jail after failing to post $100,000 bail.

Sharon police Capt. Michael Menster said he plans to charge Mortimer with criminal homicide. The charges have not been filed yet because the district attorney’s office is waiting for autopsy results, said District Attorney James P. Epstein.