DELTONA, Fla. -

Deputies are investigating after they say a 4-year-old boy drowned in a backyard swimming pool in Deltona late Sunday afternoon.

Deputies were dispatched to a home on South Fairbairn Drive after receiving a 911 call at 4:19 p.m. Sunday.

The boy's mother told the sheriff's office that she fell asleep, and when she awoke and started looking for her son she found him at the bottom of the pool, deputies said.

When the first deputy arrived at 4:23 p.m., the mother had the child on the pool deck and was trying to resuscitate him.

Authorities said the deputy took over CPR efforts until paramedics arrived about a minute later.

The paramedics continued CPR while taking the boy to Florida Hospital Fish Memorial in Orange City.

The child was pronounced dead at the hospital after 5 p.m. Sunday, deputies said.