The employee killed two men after returning from a break at the Super K store in Houston.
KPRC reports Dien Tu was at the back of the store when the thieves entered. When he was done with his break he returned to see a masked man pistol-whipping his co-worker.
According to the report the store had been robbed 10 days earlier so Tu was wearing a pistol.
Tu told authorities the robbers didn't see him until it was too late. The wounded men fled and were caught trying to flag down an ambulance. Police say they believe there may have been more thieves involved.

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