Crime scene tape surrounds a home in Penetanguishene proving something terrible took place on Monday night.

Police are stopping short of calling it a homicide, but there is no question it is a criminal investigation.

An OPP cruiser guards the home on Don Street where a  59-year-old man was fatally injured.

OPP said they arrived at the home shortly before 9 on Monday night and found a 27-year-old man injured.  He was arrested and taken to a local hospital, and later airlifted to a Toronto trauma centre where he remains in critical condition.

Police say William McKee was also found in the home with serious injuries.  He was taken to hospital where he was pronounced dead.

Investigators haven’t commented on the relationship between the men, nor will they call the 27-year-old a suspect in McKee’s death.

“We are still currently investigating,” says OPP Const. Sherri Golds.

Neighbours tell CTV News that the victim and his family were quiet and kept to themselves.

The OPP called in the Special Investigations Unit to investigate, they have invoked their mandate.