Toronto police have released security camera video taken moments before a woman was stabbed to death while walking home from work on Tuesday morning.
Video posted to YouTube shows the woman walking through a downtown laneway, followed some 20 seconds later by a male suspect.
Police say the suspect followed the woman, who was in her 50s, attacked her from behind and then repeatedly stabbed her in the arm and torso around 7 a.m.
An autopsy of the woman is scheduled for Wednesday.
Police are interviewing several witnesses, including one who tried to intervene following the assault.
Toronto police Det. Gary Giroux says police have identified the woman but are still in the process of reaching her family.
He called the death a "frightening" and "unprovoked" attack.
The suspect is described as a five-foot-10 white male, who was wearing dark clothing and a toque or cap. Police say he may still have blood on his clothing.