The incident happened late Wednesday afternoon in Brampton, northwest of Toronto, when an unidentified 28-year-old man attacked Nazifa Shahghasy, 52, as she came out of a store in a strip plaza, the Toronto Star reported.

The woman's husband, Rahimullah Shahghasy, 53, tried to intervene, and he was fatally stabbed as well, Peel Regional Police said.

When police officers arrived, the assailant refused orders to drop his knife and slashed his own throat as an officer used Taser stun gun on him. He was in critical condition Thursday, the report said.

Inspector Norm English, head of Peel Homicide said at a news conference the slain couple were "outstanding members of our community" who came to Canada from Afghanistan 20 years ago, the Star said.