GREEN COVE SPRINGS, Fla. -

A search for a missing man was expected to resume Friday morning in Green Cove Springs.

John Butler Jr., 69, was last seen Monday by patrons of a nearby restaurant located at a golf course on State Road 16 and by employees of the Green Cove Marina at Reynolds Park off State Road 16.

Butler lives on a boat that is docked on Pier 12 at the Green Cove Marina and is well-known to the employees and other residents of the area, according to the Clay County Sheriff's Office. Employees of the marina became concerned when they realized they had not seen Butler since Monday, which is unusual, and called to report their concerns.

Butler's boat has been searched and there are no signs of foul play at this point in the investigation, deputies said. Butler's personal belongings, golf cart, dinghy (used to ferry between the dock and the boat) are all there. He lives alone on the boat and doesn't have family in the area.

Authorities said they're concerned Butler may have fallen into the St. Johns River. As a result, Green Cove Springs police requested assistance from various agencies who are now assisting with the search.

Anyone with information that may help authorities is asked to call the Green Cove Springs Police Department at 904-297-7300.