Two off-duty officers stopped the men as they were walking in the middle of West 18th Street shortly before 6pm.

Chief Rick Grahm says one person tried to run away.

"The officers were just going to stop and have a casual conversation.  Obviously for some unknown reason at this time it turned confrontational".

One officer first used his taser and when the man fell to the ground, a gun fell out of his clothes.

When the subject got up, police say he pointed the gun at the officers and they opened fire.

The victim hasn't been identified and we don't know why he tried to run.

Assistant State Attorney Bernie de la Rionda is investigating the shooting, which is standard procedure. 

"We're working to determine whether there's anything criminal".

There have been eight shootings involving police in 2009.  De la Rionda says six of those incidents have resulted in no criminal charges.

Two others, including Monday's, are still under investigation.