TULSA, Oklahoma - Two men were shot and killed by a clerk and two others are in police custody after an attempt to rob a convenience store late Tuesday, Tulsa police said.

Officers said they got the call at 10:33 p.m. to Ryan's Convenience store at 9948 East 21st Street. 

The store's clerk said three masked men entered the store armed with handguns. Police said the clerk responded by firing his semi-automatic handgun, killing one and wounding another. They say the wounded man was taken to the hospital by EMSA where he later died. A third man got into an SUV and drove away.

Brian Powell is one of the men who died. Records show he was on a deferred sentence for concealing stolen property. Kevin Dobbs, 17, was named as the other person killed.

The owner of the store told News On 6 the clerk is also his nephew who has worked there several years. He said they had talked with employees about protecting themselves.

"We let them do what they feel is right for them," Mark DeLay said.

After questioning the clerk and other witnesses in the store, Tulsa Police Sgt. Mike Williams says it looks like a clear-cut case of self defense.

"It's clearly an armed robbery. The individual was wearing a mask and was armed with a semi automatic pistol. It's clearly an armed robbery." said Sgt. Mike Williams.

About a half hour later, police said the SUV returned to the scene and two men were arrested.

Police said Lakeit Thompson not only admitted to trying to rob the store, but also admitted to robbing six other businesses since the first of December. They also arrested George Williamson. Records show he admitted being the lookout during the robbery and also was involved in two other recent robberies.

Both men were booked for multiple robberies, attempted robbery and second-degree murder.

Police have recovered two handguns used by the robbers and the handgun used by the clerk.