Police in Louisiana are investigating whether 3-year-old twins who were found dead in a hot pickup truck outside their home would have been able to climb into the vehicle themselves.

Oliver and Aria Orr were found unresponsive inside the truck at their Bossier City home Saturday. They were later pronounced dead a hospital. Autopsies have confirmed the deaths were heat related.

Bossier City spokesman Mark Natale says the pickup truck wasn't used that day, and a step-stool was found next to the truck.

A neighbor tells KSLA-TV the mother said she had fallen asleep and when she woke up the door to the home was open and the children were gone.

It hasn't been determined whether charges will be filed.