Vancouver Police are looking for additional witnesses, including a woman described as "possibly having a prosthetic leg," to come forward in their investigation of a serious assault that has left a man with life-altering injuries.

Joshua Albertson, the 34-year-old victim, was punched in the face and knocked unconscious around 2:40 a.m. PT Oct. 25 in front of the Roadhouse Bar at 670 Smithe St. He fell and hit his head on the concrete causing severe injuries and brain damage.

"Every wife will say their husband is the best, but Josh truly is," wrote his wife, Nancy Albertson, on Facebook.

"He is so kind, and generous; compassionate with everyone he meets and loved by so many people."

VPD released this picture of the victim but are not naming him. (VPD)

Police say at the time of the assault the victim and his wife were walking past two groups of men who were arguing over a limousine. They say the victim is not associated in anyway with either group of men, and it's unclear why he was punched.

Cst. Brian Montague says it's the latest "one-punch" incident in Vancouver where a person has been rendered unconscious by a single punch before hitting the ground.

Montague estimates there have been 10 one-punch incidents this year alone, and says alcohol is usually involved.

"It's disturbing to us," he said. "We do have individuals coming into the city that are looking for trouble, looking for fights. In many case these are victims who are sucker punched, are not involved in any sort of consensual fight."

Police say this is the tenth 'one punch' incident in Vancouver this year.

The victim of the Oct. 25 incident underwent surgery where a portion of his brain was removed. He remains in hospital.

"The prognosis is he will have life-altering injuries, that he will be dealing with this forever," said Montague.

Investigators believe that some of the witnesses to the alleged assault provided first aid to the victim as he lay on the ground. One of these potential witnesses is reported to be a young woman who may have a prosthetic leg.

Anyone with information is asked to call the VPD Major Crime Section at (604) 717-2541.

In Australia a dramatic public service campaign has been launched by the Federal Health Department warning people about the growing problem of the one-punch or "coward's punch" as it's known there.