A 2-year-old boy was brought to the emergency room at Kaiser Hospital in Ontario in an ambulance after he was unresponsive at his home on the 1100 block of East Philadelphia Street.
Ontario Police responded at 12:07 a.m. to Kaiser due to suspected child abuse with life-threatening injuries.
The boy received a medical evaluation and was transported by ambulance to Loma Linda University Medical Center, where he died Thursday morning.
Michael Lucero, 20, was arrested at the Loma Linda location on suspicion of causing corporal injury resulting in death. He was booked at West Valley Detention Center on the charges of murder and child neglect resulting in death. He was held without bail.
Lucero is the boy's mother's boyfriend. He provided child care to the boy while the woman was at work.
The coroner's report on the cause of death was not immediately released.
The investigation was ongoing. If you have information related to the case, contact the Ontario Police Department at (909) 986-6711, or Detective Justin Johnson at (909) 395-2864.