Authorities in South Carolina have shared additional information about the deaths of twin boys who were discovered in a car parked outside a preschool Wednesday evening.

As CrimeOnline previously reported, the twin boys, since identified as 20-month-old Bryson and Brayden McDaniel, were discovered in their car seats in a vehicle parked at the  Sunshine House Early Learning Academy. They were both unresponsive and pronounced dead at the scene.

As ABC News reports, authorities provided new details about the fatal incident at a press conference Thursday, but the investigation is ongoing. Richland County Coroner Nadia Rutherford told reporters that a parent discovered the children in the SUV at about 5:40 p.m. Wednesday. She did not identify the parents or specify which parent discovered the children, but said the twins attended the preschool and appeared to be well cared-for.

The coroner said a preliminary examination indicates the children died from exposure to heat. They are believed to have been in the vehicle for up to nine hours. According to the report, the SUV was not at the daycare for the entire day, but rather at a place of employment.

“We have two very distraught parents,” Rutherford said at the news conference.

According to the report, it does not appear that the staff at the daycare had any involvement.

“We can’t speak to how or why the children were left in the vehicle for so long,” she continued. “Again, that’s why I say if this was an unfortunate accident, we pray the family can find peace. But if it was a criminal act, we will help seek justice for these babies.”

The investigation is ongoing, and authorities have not made any arrests.