RICHMOND — A body was found Friday afternoon after authorities spent hours searching for a man reported missing the previous night from a boat on the Kennebec River.

The body’s identity was not positively confirmed by the state Medical Examiner’s Office, but divers and other public safety workers were searching for Mark Johnston, 64, who was reported overdue at 9:21 p.m. Thursday. Johnston had gone out onto the river with plans to take his boat from a mooring on the river to the Richmond town docks so it could be hauled out of the river Friday.

A search got underway Thursday night, and his 32-foot recreational motor boat was found by Maine Marine Patrol officer Clint Thompson downriver from Richmond on the west side of Swan Island, with its engine running and navigational lights on. No one was on board, according to Jeff Nichols, spokesman for the Maine Marine Patrol.

Johnston was chief financial officer for Kennebec Valley Community Action Program, according to the nonprofit social service agency’s website.

Johnston was last observed on a security camera arriving at the town dock at 6:11 p.m. Thursday, according to Marine Patrol investigators.

Divers with the Maine State Police/Marine Patrol dive team discovered a body about 3:10 p.m. Friday about 20 feet from the town dock, in 15 feet of water.

Searchers including firefighters from Dresden, Woolwich and Bowdoinham as well as the Marine Patrol, Richmond police, the Richmond harbormaster, a 29-foot U.S. Coast Guard vessel, and a Coast Guard helicopter from Cape Cod searched the river by air, land and water overnight until about 2:30 a.m., when the search was suspended. It resumed Friday morning.

A Marine Patrol airplane circled over the river Friday morning as part of search efforts.

Nichols said state police and Marine Patrol divers were on the scene Friday morning, using a side scan sonar device to look underwater, near the town docks in Richmond.

He said Johnston had indicated his plans were to move his vessel from its mooring to the Richmond docks around 6:15 p.m. Thursday so it could be hauled out Friday.

His vehicle was discovered parked near the town boat launch Thursday after he was reported overdue.

His daughter, Sarah Johnston, said her father was thought to be wearing jeans and an old green jacket, likely with a hooded sweatshirt underneath, when he went missing.