Published: Feb 14, 2013 5:30 PM EST
Updated: Feb 14, 2013 6:19 PM EST

FORT MYERS BEACH, Fla.- A Lee County Sheriff's Office marine patrol boat sunk for unknown reasons on Thursday afternoon at Fisherman's Wharf, behind Doc Ford's.

Officers believe it was due to a mechanical failure, possibly in a float plug. The boat is a 21-foot contender, used for patrolling the water. 

The incident is under investigation.