A 36-year-old Centertown man is believed to have drowned after his body was found in his backyard swimming pool Monday.

The Warren County Sheriff’s Department identified the man as Michael Irvin Smith.

The discovery was made Monday around 12:15 p.m. when Smith’s girlfriend returned to their home on Apache Lane, a gravel road located off Pigeon Hill Road.

“The last time he was seen was Sunday around 1:30 p.m.,” said Sheriff’s Department Major Jason Walker. “His girlfriend went out of town for the night and that’s when she left. When she came back home she couldn’t find him and started looking.”

Walker said it is unknown how long Smith may have been in the pool. He dismissed the idea he may have gone for an afternoon swim on an unseasonably hot September afternoon.

“The pool wasn’t fit for swimming,” said Walker.

The body has been sent to the medical examiner’s office for autopsy. That will determine cause of death.

Walker said investigators aren’t sure if Smith accidentally fell in the pool or if an incident might have taken place beforehand.

“We’ll know more when the results come back from the medical examiner,” said Walker. “It remains under investigation.”