JACKSONVILLE, Fla. -

After a 2-year-old girl hospitalized with head injuries died, charges against the mother's boyfriend were upgraded to murder, according to the Jacksonville Sheriff's Office.

Brooklyn Sanchez suffered severe head trauma and died four days later.  On Saturday, the Medical Examiner's Office determined her death was the result of a blunt force head injury and was a homicide.

Devonte Baker, 20, was arrested on Dec. 15 on charges of aggravated child abuse, causing great bodily harm, permanent disability and disfigurement.  On Wednesday, Baker,, who was still in custody, was charged with murder.

Police said the girl was in Baker's care when she was injured. They said Baker told the child's parent or guardian that she had slipped and fell into the shower.

Police said when they questioned Baker, he gave different accounts of what happened that did not match up with the girl's injuries. His final version was that he had gotten frustrated with the girl because she was whining and crying after injuring her lip in the shower, police said.

According to the police report, Baker told investigators he shoved the girl to the ground and she struck the floor, according to the police report. He said he didn't call for help because he was scared and was hoping the girl would just wake up, according to the report.

Baker was rebooked on the murder charge.