Police are urging the public to help them identify a man they say tried to murder a Red River College instructor in downtown Winnipeg.

The attack, which appears to be unprovoked and random, happened Oct. 16 at King Street and William Avenue, near the college's Exchange District campus.

On Thursday, police released a composite sketch of the suspect as well as some grainy images taken from surveillance video of a person of interest.

The suspect is described as being in his late 30s to 40s with a dark complexion and dark eyes. He is five foot 11 or six feet tall, with a slender build, prominent cheekbones and black, straight and shiny shoulder-length hair, curled at the bottom. (Winnipeg Police Service)

The stabbing attack on the 42-year-old instructor was so vicious that when he tried calling 911, the amount of blood prevented him from using the phone, said police spokesman Const. Jay Murray.

"I think that just speaks to the severity of the injuries. We believe this was an attempted murder and that's how we're investigating it at this time," he said.

"These are injuries that this person will probably carry for the rest of their life and will probably be life altering."

Police said the instructor was walking around 9:20 p.m. when he was attacked from behind. He didn't say anything to the attacker so it is unclear what prompted the beating, Murray said.

The instructor tried to flag down drivers passing by during the attack but no one stopped to help, Murray said. Eventually, he got the attention of a medical professional who was passing by and provided immediate medical assistance.

Police released images of a possible suspect who was wearing a blue or purple sweatshirt with 'Canada' written across the chest. (Winnipeg Police Service)

The instructor was taken to hospital in critical condition, but later stabilized. He is now at home and recovering from his injuries, the college says.

He gave police a description of the attacker, describing him as being in his late 30s to 40s with a dark complexion and dark eyes.

He is also described as five foot 11 or six feet tall, with a slender build, prominent cheekbones and black, straight and shiny shoulder-length hair, curled at the bottom.

Police have scanned surveillance cameras from the area and pulled images of a possible suspect, who was wearing a blue or purple sweatshirt with the word "Canada" on the chest.