Green Oak Township, MI – A 73-year-old Green Oak Township man and his dog died of possible carbon monoxide poisoning Sunday, officials said.

Chief Jason Pless of the Green Oak Township Police Department said officers were called around 1:50 p.m. Sunday to a home in the 11000 block of Shorecrest Drive for a possible full arrest, but it was quickly determined the victim had been deceased a “few days.”

“A neighbor, who is an off duty fireman, became concerned because he hadn’t seen (the victim) in a few days,” Pless explained. “The door was unlocked and he walked in and saw the dog dead and then found the man.”

The last contact neighbors had with the 73-year-old man was on Thursday, Pless said, declining to identify the victim.

The chief said the fire department’s preliminary investigation indicated “elevated levels” of carbon monoxide in the home. The source is believed to be the water heater.

A message to the Green Oak fire chief was not immediately returned Monday.