CHATHAM, Mass (NECN) — The body of a man who had been missing since last year was found Monday on a Coast Guard boat on display at the U.S. Coast Guard Station in Chatham, Massachusetts.

The Cape & Islands District Attorney's Office said the discovery of a decomposed body was made in a closed compartment on the boat just before 9 p.m. Sunday.

The mother of 24-year-old Matthew Amsler, who went missing last October, confirmed to NBC Boston that it was her son's body that was found Monday. Amsler went missing after reacting badly to medication he was taking for schizophrenia. He had last been seen in the area of Lighthouse Beach.

Boat that missing man was found in is at U.S. Coast Guard Museum in Chatham, Mass.

Neighbor Jack Cushing, who helped search for Amsler after he disappeared, had hoped for a different outcome.

“Nobody had any idea what actually had happened,” Cushing said. “It's a terribly sad thing.”

Condolences are already pouring in on social media. One family member said he crawled into an airtight space on the boat for shelter from a storm and fell asleep and ran out of oxygen.

Authorities said they have yet to make an official identification. The body has been sent to the state medical examiner in an effort to determine its identity

The 44-foot-long boat where the body was discovered on is a "museum piece" and cannot be moved because it is secured to the ground, according to a Coast Guard spokesperson. The boat was retired in 2009 after 46 years in service.

Although preliminary evidence doesn't suggest foul play, the investigation is ongoing.

Amsler leaves behind a wife and 2-year-old daughter.