Peel Regional Police say the victims of a double fatal stabbing in Brampton, Ont., were a husband and wife originally from Afghanistan who didn't know their attacker.

Police originally said a Good Samaritan ran over to help a woman who was being stabbed at a strip mall, but at a news conference on Thursday, investigators said the man was the woman's husband.

Insp. Norm English said the pair went to the strip mall at 20 Red Maple Dr., near McLaughlin Road and Williams Parkway, over the noon hour Wednesday for medical appointments.

While the woman was inside a dentist office, her husband went to go and buy some food next door. It was when she was walking back to her vehicle that she was attacked by a man.

"The attack was completely unprovoked," English told reporters. "The husband saw what was happening and tried to help his wife, but was overcome by the male."

Both victims, Nazifa and Rahimullah Shahghasy, were in their early 50s and lived in Brampton. They died at the scene.

English said the 28-year-old suspect, who was carrying two kitchen knives with 10-inch blades, then began to stab himself in the neck.

Officers arrived and Tasered him, causing the suspect to fall to the ground. The suspect, who also lives in Brampton, was taken to hospital with serious injuries but is expected to survive.

"He will be formally charged with second-degree murder once his condition improves," English said.

Investigators had not yet had a chance to interview the suspect by Thursday afternoon.

English said the suspect is known to police for a "variety of criminal matters," and was facing an outstanding violent offence at the time of the incident.

English didn't have details about the suspect's whereabouts before the double stabbing.

The Shahghasys had lived in Canada for 20 years and are originally from Afghanistan. They have two children, a 21-year-old son and a 19-year-old daughter.

English described the slain pair as "wonderful people."

One of Nazifa co-workers said there is unbelievable heartache at their workplace.

"I think it's a nightmare," co-worker Shahida Malik told CTV Toronto, wiping away tears. "Now she's gone, she's gone."

A cousin of the victims said the ordeal is "beyond belief."

"You're at a loss," the man said. "You can't put it into words, you can't put it into terminology that's understandable with language."

On Thursday, one white and one yellow rose sat beneath a tree near the crime scene.

The SIU is involved in the investigation because of the confrontation involving Peel officers and the suspect.

With a report from CTV Toronto's Austin Delaney