WEST MEMPHIS, Ark. (KTHV) - A 5-year-old boy has died in West Memphis after he was found unresponsive inside a day care van according to CBS affiliate WREG.

Police say the boy was picked up around 7:00 a.m., but wasn't found until around 3:30 p.m. when staff at Ascent Children's Health Services were preparing to bring kids home.

They say two adults were in the van, the driver and the monitor, during the initial pick-up, but missed the 5-year-old when they were escorting children off the bus.

Officer believe the child was asleep, but are unsure if he simply never woke up or became disoriented at some point.

"He had no disabilities that prevented...he was mobile, he was vocal," said West Memphis Police Captain Joe Baker.

The temperature in West Memphis on Monday reached 91 degrees and police said the inside of the van could have gotten up to 130 degrees.

Both the West Memphis Police Department and the Department of Human Services are investigating possible negligence by multiple people.