LAKELAND, Fla. (AP) - Two toddlers who were found in their grandparents' swimming pool have died.

The Polk County Sheriff's Office says 18-month-old Silas Lugo-Walsh was pronounced dead late Saturday. His 2-year-old cousin Jayvien Watkins was pronounced dead about an hour and a half later Sunday.

Deputies say the boys were missing for about 10 to 15 minutes before family members realized they were gone Friday evening.

The relatives began searching frantically and found the children face down in the pool. The pool had a fence around it, but Sheriff Grady Judd said the gate appeared open.

He called the incident a “tragic, tragic accident.”

The investigation is ongoing. Autopsies will be conducted on both boys.