SANIBEL, Fla.- The 2-year-old boy who was found unresponsive in a Sanibel swimming pool on Monday evening has died.

Bystanders found Kade Davis in the pool at the Sanibel Arms Condominiums, just before 9:30 p.m. on Monday. They performed CPR until medics arrived, authorities say.

Davis was brought to HealthPark Medical center, where he was placed on a ventilator, until Thursday when he passed away.

The toddler, who was expected to turn 3 next month, was visiting Southwest Florida with his grandparents. His parents were at their home in Louisiana at the time of the accident, according to Sanibel Fire officials.

A family friend who witnessed the incident says Davis pulled off his water wings, causing the event.

Police were on scene Tuesday morning questioning witnesses.

The Sanibel Police Department says it is an open investigation, but it does not appear to be a suspicious situation.