Officials with the Alberta Serious Incident Response Team are looking for the public’s help in another shooting involving Calgary police officers on Saturday, the second such incident in a week.

At about 11 a.m. on March 21, a man approached the members of an anti-racism rally taking place outside Calgary City Hall and created a disturbance, shouting white supremacist slogans.

Police followed the man to an alley, between 7 and 8 Avenue S.W., and attempted to speak with him.

At that point, the man pulled out a metal pipe and attacked the officer with it.

The officer used his baton, but then had to pull his gun, shooting and wounding the man.

During the incident, police say the officer did make a distress call.

ASIRT investigators say they are seeking to speak with anyone in the area of Centre Street and 8 Avenue S.W. who may have heard or seen something that could help them piece together what happened.

“The dynamics of what exactly occurred in that alleyway are very important to determining what happened and determining how appropriate the use of force was,” said Susan Hughson with ASIRT. “It's a location where there are hotels. It's a public area, so we're hoping to get the best picture possible of what exactly what happened in that alley from as many perspectives as possible.”

The man remains in critical condition in hospital. He has not been identified and there is no word on charges against him.

ASIRT asks anyone with information to contact them at 403-592-4306.

This is the second police-involved shooting in Calgary in the past week.

On Monday, police shot and killed Anthony Heffernan, 27, inside a room at the Super 8 Motel on Barlow Trail N.E.

Officers say they attempted to subdue him with Tasers after he came at them with a needle.

Their method didn’t work and they were forced to shoot, killing him.

That investigation is also ongoing.