Willie Brown (Credit: Cook County Sheriff)

Willie Brown (Credit: Cook County Sheriff)

CHICAGO (CBS) — A teenage boy started playing video games after the severely battered baby he was caring for stopped crying and eventually died last week, Cook County prosecutors said Tuesday.

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Willie Brown, who is facing murder charges in 4-month-old Demari Brown’s death, was the primary caregiver of the child when he was watching him in his girlfriend’s home in the 6000 block of South Honore last Thursday, Assistant State’s Attorney Heather Kent said.

Police said Brown was the dead child’s father. But Kent said Demari is Brown’s girlfriend’s baby.

When Demari’s mother asked Brown what he did to her baby at the hospital where the infant was transported, he allegedly cried and said, “I’m sorry. I’m sorry,” the Sun-Times is reporting.

Brown was the only one with Demari in his bedroom when the crying Demari suddenly stopped making sounds, Kent said.

Brown left the bedroom and went to play video games, Kent said.

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A short time later, someone else went into the bedroom and found that Demari was unresponsive, Kent said.

Demari suffered blunt trauma to the head, a linear fracture to the skull, subdural hemorrhages, rib fractures and healing fractures to other ribs and a wrist.

An autopsy determined Demari died from multiple blunt force injuries caused by child abuse, and his death was ruled a homicide, according to the medical examiner’s office.

The state Department of Children & Family Services was investigating the boy’s mother, Brown and grandmother for allegations of abuse, spokesman Dave Clarkin said. The agency has had no prior reports regarding the family.

Brown, of the 2400 block of West Gladys, was ordered held in lieu of $500,000 bail.

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(Source: Sun-Times Media Wire © Chicago Sun-Times 2013. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)