A man had his AR-15-style rifle stolen at gunpoint. He then used a second gun to open fire on the robber, police say.

• A man who was open-carrying an AR-15-style rifle in Missouri was robbed at gunpoint, police said.
• After his gun was stolen, police said the victim retrieved another gun from his car.

A man who was open-carrying an AR-15-style rifle at a Missouri supermarket had his firearm stolen at gunpoint, according to police.

Then, in a surprising twist, he retrieved another gun from his vehicle, and opened fire on the man accused of robbing him, North County Police Cooperative said on Facebook.

Officers responded on May 27 after a call for "shots fired" at Wellston Food Market in St Louis, Missouri.

Officers said that a man had been carrying his rifle around the supermarket in a non-threatening manner.

When he stepped out of the store, a 31-year-old man held a pistol to the back of his head, according to a probable cause statement, per the NBC affiliate station KSDK.

He then stole the victim's jacket and gun, the probable cause statement said, KDSK reported.

After giving the rifle up, police said the victim grabbed another gun he had in his car and opened fire on the accused robber.

A shootout ensued, police said, during which two bystanders — both women — were struck. The injuries were not life-threatening.

The victim fled with his rifle while the accused robber, who had been shot several times, remained on the scene. A third man then also shot him, police said.

The accused robber is charged with armed criminal action, first-degree robbery, and two counts each of unlawful use of a weapon and unlawful possession of a firearm, KSDK reported. His cash-only bond was set at $500,000, the local media outlet said.

"This is a very active and fluid investigation," said the North County Police Cooperative on Facebook.