Police are appealing for witnesses after a man was sucker-punched while walking with his wife in downtown Vancouver – and suffered permanent life-altering injuries as a result.

Const. Brian Montague said the couple was walking home after a night out with friends in the early morning hours of Oct. 25 when they passed by two groups of men arguing over a limousine outside The Roadhouse bar on Smithe Street.

For no apparent reason, and with no apparent provocation, the 34-year-old husband was attacked.

“As my victim walked by with his wife, the attention was turned to them,” Montague said.

“One of the men in the group turned and punched our victim once in the head. He was rendered unconscious before he hit the ground.”

The victim hit his head on his way down and suffered a serious brain injury. Police said he has since undergone surgery to relieve pressure in his head, and had a portion of his brain tissue removed.

Nearly a month after the attack, he remains in recovery in hospital.

Montague said the incident is just the latest in a string of separate “one-punch” attacks, of which there have roughly 10 so far this year. Three of those were fatal, including an incident outside Shenanigans Nightclub on Robson Street that killed a 60-year-old man in August.

Last week, police arrested a 23-year-old suspect from Coquitlam in connection with the attack outside The Roadhouse, but investigators believe there are more witnesses who can help strengthen their case.

Montague said police are hoping to speak to two limo drivers who were parked at the scene, as well as Good Samaritans who tried to provide first aid to the victim.

One potential witness is described as a young woman who may have a prosthetic leg.

Montague said the “one-punch” attacks haven’t been limited to one area of the city, and have been reported in the Granville Entertainment District, Gastown, and the West End.

The common factor in all of them appears to be alcohol.

“This could happen to you or me walking down the street. There is that possibility,” Montague said. “We do have individuals that come into the city that are looking for trouble, that are looking to get into fights, and unfortunately this is the result sometimes.”

Anyone with information on the Oct. 25 attack is asked to contact the Vancouver Police Department’s Major Crime Section at 604-717-2541.