ROCKLEDGE, Fla. -

Charges against a Rockledge father accused of leaving a 9-month-old girl alone in a hot vehicle for hours were upgraded to third-degree murder, officials announced on Friday.

Steven Lillie was initially arrested in June on charges of aggravated manslaughter in the death of his daughter, Anna Marie Lillie. In addition to murder, Lillie also faces a charge of leaving a child unattended or unsupervised in a motor vehicle.

Lillie found his daughter unresponsive in his pickup truck outside his workplace at 566 Barton Boulevard, according to police, who said Anna  had been left inside the closed truck for about four hours during the hottest time of the day.

Paramedics rushed the girl to Wuesthoff Hospital, where she died.

Police told WKMG-TV that Lillie left for work intending to drop his daughter off with a caregiver.  Some type of disruption in Lillie's normal routine, however, caused him to forget that he had not dropped off the baby, police said. 

About four hours later, a family member asking about the girl prompted Lillie to run outside, where he found his daughter inside the truck, police said.