A 65-year-old man was found dead inside a burning motor home at a campground in the Florida Keys.

Monroe County Sheriff's deputies responded to reports of a fire at Seahorse Campground on Big Pine Key late Thursday. They spotted a body on a mattress inside the motor home, but couldn't get inside because of intense smoke and heat. 

Fire rescue officials later retrieved the body of the man, whose name has not been released. 

A neighbor told deputies he had spotted the smoke and put out the flames with a fire extinguisher. Another neighbor called 911. 

The state fire marshal's office will investigate.