CAPE GIRARDEAU, Mo. (AP) – A 10-week-old Missouri girl has died after being left inside a hot vehicle.

Siblings found the infant Saturday afternoon inside a vehicle at Parkwood Lake Estates trailer park in Cape Girardeau, about 100 miles south of St. Louis. She was pronounced dead at a hospital.

The child’s name has not been released.

An autopsy Sunday cited hyperthermia as the cause of death. Hyperthermia occurs when a body absorbs more heat than it can dissipate and organs shut down. The high temperature in Cape Girardeau on Saturday was 91 degrees (33 Celsius).

Authorities aren’t sure how long the child was left in the car, and did not say who left her there. No arrests have been made and an investigation continues.