Four-year-old Keyontay Miller-Peterson of Burnsville died of blunt-force trauma to the abdomen and his death was a homicide, the Hennepin County Medical Examiner said Thursday.

The boy died at the home he shared with his mother on Horizon Heights Road on June 11. Police were called to the townhouse about 5 p.m. on a report of “medical problems.” The boy was dead when officers arrived.

The mother’s boyfriend, 24, was arrested as he tried to drive away from the home. Police said then that he was the only suspect, but he has not yet been charged in connection with Keyontay’s death.