WORTH TOWNSHIP, MI -- A man walking on a Lake Huron beach discovered a body, giving investigators and relatives a vital clue about the mystery of a sinking ship and a missing man.

Investigators believe the body is that of Patrick Presutti, a Macomb man who went missing about Aug. 30 or Sept. 1, days before his 31-foot Sea-Ray luxury cruiser was found sinking on Sept. 7, police say.

"I am hopeful that after the official identification and over a month of waiting, it will finally bring closure to the family," Sanilac County Sheriff Gary Biniecki said.

Deputies recovered the boat after a passing freighter found it Sept. 7, partially submerged in Lake Huron near Forestville.

Police asked the public for help in locating the boat's owner. Presutti was last seen leaving a Lake St. Clair marina on Sept. 1, police said, on the boat.

About 11:49 a.m. Sunday, Oct. 4, Sanilac County Central Dispatch received a phone call from a man reporting that a body had been found on the beach by people out walking.

The caller led police to the body, which was partially submerged near the 6200 block of South Lakeshore off the east coast of Michigan's Thumb, about 100 miles northeast of Detroit.

The cause of death is yet to be determined, pending an autopsy scheduled for Tuesday, Oct. 6. The Sanilac County Sheriff's Office and the Macomb County Sheriff's Office continue to investigate.

Detectives believe someone intentionally tried to sink the boat, the Sanilac County Sheriff's Department reported after an initial investigation.

A strainer was left open inside the boat, according to Macomb County Sheriff's Department investigators. The strainer had been secured with "wingnuts" that were undone, allowing water to come inside the boat, police said.

A black-and-white Jolly Roger flag was fixed to the bow. A photograph of a Jolly Roger flag, like the one on the front of the sinking Sea Ray, is Presutti's Facebook cover image.

Presutti is pictured on his Facebook page wearing a Sea Ray hat behind the wheel of a boat. The profile states he is from New Baltimore and lives in Macomb. He studied at Oakland University and lists sales manager as his occupation at multiple car sales locations.

Anyone with information is asked to call the Macomb County Sheriff's Department Detective Bureau at 586-307-9358.

The Lexington Police Department and the Lexington Fire Department assisted the sheriff's department in recovering the body.

-- Brad Devereaux is a public safety reporter for MLive/The Saginaw News. Follow him on Twitter, Facebook and Google+