Peel Regional Police tracked an off-duty member of their service who they said was "in crisis" to Hamilton, where he was stopped at a rural gas station.
A tense standoff was peacefully resolved shortly before 6 p.m. ET, Peel police said
With the assistance of Hamilton police and other forces, the officer was stopped in the area of Peters Corners, near Highways 5, 52 and 8, just behind Gord's Service Centre in rural Hamilton.
Owner Bill Hume was pumping gas around 4 p.m., he said, when he was approached by a Peel Regional Police officer.
"[He] walked over and asked that everyone get in the building, that they had a situation happening. So I got everyone in the building and looked out. The police had everything closed off and building surrounded and they had done it very well, there were no sirens, no noise it was done very quietly."
Hume said he hadn't noticed the "officer in crisis" had pulled in ahead of the cruiser to the back area of his lot. Many more cruisers followed as Hume, his wife, their two sons and several employees stayed inside the station's offices. He said he was told that police believed the officer was armed. He watched the tactical team deploy very quickly as negotiations with the officer were set up.
"I've never seen so many Peel police cars in my life," he told CBC News in Hamilton.
"There are TV shows that show situations like this. This was a real-life performance. I'd just as soon watch it on TV."
Officers from five police forces were involved: Halton, Peel, Ontario Provincial Police, Hamilton and York.
Highway 5 was closed during the incident.
"It originated in our jurisdiction," said Peel police Const. Fiona Thivierge. "Because we came through highways, OPP are involved. Once it entered Hamilton area, Hamilton police became involved. That's just because we are entering each jurisdiction and we have to notify that police service that we are in the area. And they assisted with road closures and things."
She would not confirm if the officer was armed.
"The officer was in crisis and we are glad to report it was resolved without incident," she said, adding he is getting the assistance required. She said the officer was in his own personal car and at no time was the public at risk.