The skeletal remains of Julius Colwye were found inside his sunken 1970s Buick sedan when it was pulled from a pond in Michigan's Buena Vista Township on August 15

Police say human remains found in a submerged car in Michigan last week belong to a man who went missing in the 1980s.

The skeletal remains were found inside a sunken 1970s Buick sedan when it was pulled from a pond in Buena Vista Township on August 15.

Police said there was a 'high probability' the badly decomposed body was that of local man Julius Colwye following forensic pathology tests and a dental forensic exam.

Colwye, a 61-year-old grandfather, was reported missing from Buena Vista Township on October 1, 1984.

Following the discovery of his remains, police are treating Colwye's death as suspicious.

Police are still not clear on the cause or manner of Colwye's death but say the car had likely been at the bottom of the pond for years.

The badly decomposed remains of Julius Colwye were found inside his 1970s Buick sedan (above) when it was pulled from a pond in Michigan's Buena Vista Township on August 15

Colwye, pictured with his then-six-year-old grandson Marcel, was 61 when he was reported missing from Buena Vista Township on October 1, 1984

'It's hard to tell, but it's been there for a long time, any number of years,' Michigan State Police Lt. Dave Kaiser said.

Missing persons reports from the time he disappeared stated that no withdrawals had been made from his bank account and his retirements checks had not been banked

Authorities are still trying to piece together the events that led to Colwye's body ended up trapped inside his car.

Missing persons reports from the time he disappeared stated that no withdrawals had been made from his bank account and his retirements checks had not been banked.

His Buick had also not been spotted.

When the vehicle was pulled from the pond last week, Colwye's family immediately told police they believed the remains were his.

His grandson Marcel Colwye, who was six when he went missing, told MLive.com that his mother saw news reports and went straight to the scene.

'She came to my job and when I saw her I knew something was wrong,' he said. 'She told me they found the car and showed me the picture.

Police have labeled the death as suspicious and are still trying to determine how the car got into the water

'The first day he didn't come home when I was six, I knew something was wrong because that wasn't normal... And nobody could tell me where he was.'

Marcel said the discovery brought a sense of relief but also raised more questions.

'It's bittersweet. It's good to know, but now that we know where he was at, we want to know how he got there. And when we find out how he got there, I want to know why,' he said.

Michigan Department of Transportation workers were removing barrels with unknown contents from the pond last week when they found the rotting human remains trapped inside.

The pond is on state property roughly 80 miles northwest of Detroit.

The pond is on state property roughly 80 miles northwest of Detroit (pictured)