BREAKING: Toronto cop shot and killed, suspect in custody

The Ontario SIU has invoked its mandate, tweeting: "The SIU has invoked its mandate in relation to a shooting involving a Halton Regional Police Service officer this afternoon on York Blvd in Hamilton. Media officer en route to scene."

A civilian was also shot, though it is not known if it was during the original incident, which was reportedly a carjacking outside of a Tim Hortons restaurant at Argentia Rd. and Winston Churchill Blvd, or in the moments after.

Halton police issued an Emergency Alert, though the suspect was quickly apprehended. Police say that one person is dead and two others have been hospitalized.

"According to sources, three people — all civilians — were shot in a plaza in Milton. There was no immediate information on the extent of their injuries," reports The Sun.

The officer who was shot was leading a training class for motorcycle officers. "They just stopped for lunch when someone came in and shot at the officers," said one source.