ORANGE CITY, Fla. -

A diver drowned after a failed attempt at "buddy-breathing" while exploring an underwater cave at Blue Spring State Park in central Florida.

Volusia County Sheriff's officials say 36-year-old Samuel Slack experienced equipment problems while diving 80 feet below the surface Wednesday.

The Daytona Beach News-Journal reports diving partner Daniel Vansickle says Slack made a "throat slash" gesture, signaling he was having difficulty breathing.

A sheriff's report says Slack passed his air regulator to Slack, who wouldn't release it back to Vansickle after about 30 seconds. Vansickle pulled the regulator away, swam to the surface, and yelled for someone to call 911. He dove again and found Slack on his back.

Vansickle carried Slack to the surface and tried unsuccessfully to revive him. He was pronounced dead at a hospital.