SOMBA K'E/YELLOWKNIFE - A 55-year-old man is in a coma after being found unconscious on the sidewalk Tuesday morning.

The man was found on 51 Street near Simpson House just after midnight. He was quickly transported to the hospital for treatment of a head injury and later medevaced to Edmonton where, as of Thursday, he remained in serious condition.

RCMP Const. Kathy Law said police are still investigating the cause of the injury. It remains uncertain whether the man was a victim of a possible assault or whether, for example, he hit his head when he fell.

Law said police are currently seeking the woman who flagged down a motorist for assistance.

"We're requesting the female ... please contact the RCMP detachment just in case. We don't know if she saw anything, we'd just like to get a statement if possible," she said.

Likewise, anyone with any information relevant to the investigation is asked to contact the police.

Earlier this month, police found 28-year-old Derrick Sangris unconscious and badly injured on 50 Street outside of Corner Mart. He was medevaced to Edmonton for treatment.

While Sangris remained in a coma for several days, he is now expected to make a full recovery.

Police are still investigating the assault.