MASON, Ohio (AP) — A five-year-old boy with autism who was found in a retention pond has died, authorities said.

The Warren County Sheriff’s Office said deputies were dispatched to a Deerfield Township residence at about 7 p.m. Friday after the child was reported missing.

Deputies and fire rescue units searched the area and eventually found the boy in a retention pond, the sheriff’s office said.

Sgt, Brian Hounshell said the boy later died at a hospital. Officials said the investigation is still going on, but the death appears to have been a tragic accident.

The Mason City Schools district posted condolences for the family “in what we know is unimaginable grief.” They praised the preschooler, saying “he expressed care and concern for his teachers and classmates, always ready to offer a hug and kiss a ‘boo-boo.’”