Police in Delray Beach identified the boy on Sunday as Khayden Saint Saveur.
Police arrived at the scene in the Rainberry Woods section of Delray Beach, a community that lies 50 miles north of Miami, at approximately 3:20pm on Saturday.
A police spokesperson said that when officers arrived, they noticed Khayden was unconscious inside the car.
Because the front doors were unlocked, officers were able to open the door and pull him out of the vehicle.
Khayden was rushed to Bethesda Memorial Hospital, where he was pronounced dead a short time later.
Khayden was playing with other family members and may have been in the car for up to two hours when his family realized he was missing, according to police
Police said that one adult was home at the time Khayden is believed to have wandered outside to the driveway and opened the car door on his own.
Investigators said they are still examining evidence and have yet to reach a definitive conclusion.
