By Ken MacLeod, WBZ-TV NewsBy Ken MacLeod

DEDHAM (CBS) – The parents of a Dedham man found dead in a river say they have evidence showing his death was no accident.

Gregory Hart’s body was found last spring. Investigators say he fell into the Woonasquatucket River in Providence after a night of drinking at a bar.

READ MORE: Johnson & Johnson Vaccine 'Particularly Good For Mass Vaccination Campaigns,' Boston Doctor Says

But the family told WBZ-TV they don’t buy that story.

John Hart has kept the clothing found on his son’s body, hoping the muddy T-shirt and contrasting clean dress shirt will eventually refute the police version of what happened.

“Something is covered up here. My son was murdered,” he said.

It was back in March, when UMass grad Greg Hart ventured to the Red Room nightclub in Providence where, police say, he got very drunk and then somehow tumbled into a fenced-off river nearby and drowned.

“You can’t fall into this river. So I need to know what really happened,” Greg’s mother Marianne said.

His partially submerged body was found a mile down river a few days later.

But now a Cambridge computer forensics firm hired by the family has recovered data from Greg’s battered iPhone, indicating it was never in the water.

“The fact that the phone has never been in water really contradicts those police reports,” Marianne Hart told WBZ.

READ MORE: Police Search Woods After Man Fired BB Gun Behind Salem Walmart

Actually, the initial police report said the phone was found in the bar’s parking lot. A later version said it was found in Greg’s pocket.

Making matters more complicated, the trio of friends with Greg that night won’t talk to his family about what happened at the bar.

The family suspects somebody beat their son and later dumped him in the river.

They admit to having little faith in the police probe.

“There has been no investigation. They’ve been very antagonistic right from the start,” Marianne Hart said.

Providence police didn’t return our call for comment.

The medical examiner said Greg Hart drowned with a blood alcohol three times the legal limit and the wounds on his body came from the river, after his death.

As he stands in his son’s bedroom in their Dedham home, John Hart said the mystery eats at him night and day.

MORE NEWS: Wellesley Man Killed In Ipswich Mountain Bike Crash

“Completely. It’s ripped the whole family apart.”

Ken MacLeod