BLYTHEWOOD, S.C. (AP) — Investigators say twin 20-month-old boys found dead inside a car in the parking lot of a South Carolina daycare had likely been in the hot SUV for more than nine hours.

Authorities say a parent discovered the toddlers in rear-facing seats shortly after arriving Wednesday afternoon at the Sunshine House Early Learning Academy in a Columbia suburb.

Richland County Coroner Nadia Rutherford says Bryson and Brayden McDaniel likely died from exposure to the heat. She says the parents of the twins are distraught.

Richland County deputies are investigating the deaths. No arrests have been made and deputies didn’t release any other details.