A 39-year-old man fatally stabbed Tuesday evening was out for his regular evening walk and appears to be the victim of a robbery gone wrong, Toronto police say.

Mark Ernsting, 39, died after he was attacked near 38 McGill St., just east of Yonge Street and close to Ryerson University, around 9:30 p.m. ET.

Police say he was stabbed multiple times, including at least once in the head. 

"There was no previous relationship between the accused and the deceased," Det. Paul Worden told CBC News. "The deceased was just out for his normal evening walk and happened to come across the accused and he was attacked."

CBC News has confirmed that Ernsting worked for the Ontario Institute for Cancer Research.

He was also an adjunct professor at Ryerson University where he worked with graduate students in the electrical and computer engineering department. 

About an hour after the attack, police arrested Calvin Michael Nimoh, 21, near Yonge Street and Summerhill Avenue. He is charged with second-degree murder and appeared in court on Wednesday. 

Investigators believe Nimoh, who is known to police, may have tried to rob Ernsting.

Calvin Michael Nimoh

Calvin Michael Nimoh has been charged with second-degree murder in connection with the fatal stabbing of Mark Ernsting. He appeared in court on Wednesday. (Pam Davies/CBC)

'Pool of blood' outside driveway

Barbara Galbraith, who lives in the area, says she had just come into the kitchen around 10 p.m. when she saw police outside and noticed blood on the sidewalk.

"It had just happened," Galbraith said. "The pool of blood was right outside my driveway."

Galbraith said the incident was very unnerving and that the area is generally safe.

"It's well lit, it's so close to Yonge Street and there are always people around," she said. "Police are very good about patrolling the area. I've been here 15 years and nothing like this has ever happened."

In a written statement Ryerson University said: "Those who knew and worked with Mark said he was a wonderful colleague and an excellent researcher." 

Friends and coworkers have been posting messages of condolence on social media. 

With files from CBC's Linda Ward