BATON ROUGE, La. (WAFB) – The Baton Rouge Coroner’s Office has officially ruled the death of an 8-month-old left in a car accidental.

According Coroner Beau Clark, preliminary tests show that 8-month-old Raylee Mercer died from hyperthermia.

Mercer died Wednesday after her father, 31-year-old Marvin Mercer, accidentally left her inside of his car while he was at work.

He told police he was supposed to drop her off at daycare on his way to work, but forgot and went straight to work. According to the probable cause report, he realized he left his daughter in the vehicle when he returned to go to lunch.Mercer was arrested and taken to the East Baton Rouge Parish Prison where he was booked with negligent homicide. He has since bonded out.