The Phoenix Police Department says a witness shot and killed a man who was trying to rob a Walgreens on Tuesday night.

The incident happened around 7:10 p.m. at the store near 35th Avenue and Union Hills.

According to police, 30-year-old Stephen Holguin approached the Walgreens pharmacy counter and demanded oxycodone while holding a gun. The suspect was wearing a wig at the time.

The armed customer who shot the suspect is cooperating with police as they continue to investigate. No other injuries are reported.

Life-saving efforts were performed on the suspect who died from his injuries at the scene.

There were about a dozen people inside the store at the time of the robbery and shooting.

Deadly force can be used to defend yourself or others in the state of Arizona; police are investigating the incident. No charges have been filed against the witness who shot the suspect.

Walgreens says they will not be releasing a statement because it doesn't comment on ongoing investigations.

Stay with ABC15 and abc15.com for the latest on this developing situation.