MISSISSAUGA, Ont. -- The province's police watchdog says an officer "acted responsibly" during an interaction with a 52-year-old man who was found dead hours later.

The Special Investigations Unit says provincial police officers patrolling in Grand Bend, Ont., early on July 26, 2015, encountered a man who appeared to be intoxicated but coherent.

The SIU says the officers attempted to get a taxi to take the man home, but when they couldn't locate a cab, one of the officers drove the man home and left him in the care of his mother.

A few hours later, the man's mother found him without vital signs and a post-mortem determined the man had died of a drug overdose.

SIU director Tony Loparco says he's satisfied that the officer conducted himself with due care and regard for the health and safety of the man at all times.

Loparco says the officer took it upon himself to ensure the man made it home safely by escorting him in his cruiser, and left the man in the care of his mother.

"In the circumstances, I am unable to find fault with any aspect of the subject officer's decision-making, and I am satisfied that the officer acted responsibly," Loparco said Friday in a release.

The SIU is an arm's length agency that investigates reports involving police where there has been death, serious injury or allegations of sexual assault.