A child died Monday in what an Oakville day care is calling a tragic accident after possibly being left in a car all day instead of being dropped off at day care.

An autopsy was performed today — Tuesday, Sept. 12 — on the 1-year-old boy, who was identified late Tuesday as Tate Mitchell of the 5000 block of Ivondale in Oakville. Police say they found Tate unresponsive at the Casa Dia Montessori School, 610 Kinswood Lane, at roughly 5 p.m. Monday, Sept. 11.

The boy was transported to St. Anthony’s Medical Center while paramedics tried to revive him, but he was pronounced dead at the hospital, police and the day care said.

In a statement, the school said that the child’s mother arrived for student pickup at the school at 4:55 p.m. Monday unaware that her child was already in her van unresponsive. Once she realized what had happened, the boy was taken inside the school, where school officials tried to revive him with CPR and called 911. Police received the call as a “sick case.”

The 911 caller said that the baby had been left in a car since morning and was not breathing, police said.

“All of our hearts are so saddened by this tragedy,” the school said. “And we grieve with this family at the terrible loss of this child. Please keep them in your thoughts and prayers.”

Throughout the country, incidents of parents accidentally leaving children in cars are sometimes treated by authorities as accidents and sometimes as crimes.

The investigation into the child’s death by the St. Louis County Police Department Bureau of Crimes Against Persons is “currently very active,” police said. Officers from the South County Precinct responded to the scene.

Anyone with information about the incident is asked to contact the St. Louis County Police Department at (636) 529-8210 or CrimeStoppers at 1-866-371-TIPS (8477).