Police are trying to identify a woman who provided first aid after a Halloween night stabbing in downtown Vancouver that left a 25-year-old man dead.

The incident started around 2 a.m. Nov. 1 outside the Plaza of Nations, where a fight broke out between two groups of men. Three people suffered serious stab wounds and one of them, Burnaby resident Hansen Jia Chen, died of his injuries.

Before police and paramedics arrived at the scene, an unidentified woman tried to help Chen near the taxi stand in front of the plaza. Witnesses told police she identified herself as a nursing practicum student at the B.C. Institute of Technology.

Investigators said they need to speak with her as a witness, but months after the incident they still have yet to identify her.

They are also asking anyone with cellphone video of the area near the Plaza of Nations between 9 p.m. and 2 a.m. on Halloween to come forward and assist in their investigation.

After the incident, a number of people were taken into custody, some with bags over their hands to preserve evidence, but police said none of them were cooperative.

It's unclear if either of the groups of men came from the Edgewater Casino or Prive nightclub, both of which are near the scene of the fight.

Anyone with information can contact detectives from the Vancouver Police Department at 604-717-2500.