A 21-year-old Nicetown man, who police said fatally struck a toddler he had been disciplining, was formally charged Sunday with murder.

Malik Powell, of the 3800 block of North 18th Street in Philadelphia, was charged with killing his girlfriend's son, 20-month-old Rashaan Anderson, Friday afternoon.

Police initially were told the child had fallen out of bed. But they said Powell admitted that while showering the child, he struck the boy in the chest for misbehaving, causing the toddler to fall into the tub.

The child was pronounced dead about 5 p.m. Friday at Temple University Hospital. The Medical Examiner's Office ruled the death a homicide, caused by blunt-force impact to the torso.

Powell, who also uses the name Hakim Jones, was formally arraigned Sunday and charged with murder and endangering the welfare of a child. A preliminary hearing is scheduled for July 21.

Police did not disclose the mother's name. A knock on the door of the couple's rented house went unanswered Sunday afternoon. Neighbors said the couple had moved into the house only in recent weeks.

Powell's arrest was the second time last week he was charged with a crime. According to court records, he was charged Wednesday with the unauthorized use of a vehicle, and released without bail.

He was charged in 2007 with theft, receiving stolen property, and unauthorized use of a vehicle. The charges were dismissed in 2008.