The Florida Highway Patrol is investigating a "possible fatal" motorcycle crash in Marathon.
Lt. Kathleen McKinney said the male rider lost control of his 2013 Harley Davidson trike around 8:30 a.m. at 8900 Overseas Highway. No other vehicles were involved in the wreck.
The unidentified 68-year-old man from Kilmarnock, Va., was airlifted to Ryder Trauma Center in Miami, McKinney said. His condition is "extremely critical."
McKinney said he was not wearing a helmet.
The outside northbound lane near mile marker 51 was shut down for about 45 minutes while FHP troopers investigated the crash.