The incident happened just before 8:30 p.m. at Island Thrift on Middle Country Road in Centereach.
Police say the suspect entered the store and pointed a shotgun at the manager and five other employees of the store, demanding money.
The manager, fearing the situation was becoming dire, grabbed the shotgun. Two employees joined the struggle, gained control of the weapon and wrestled Kelly to the ground, holding him down until police officers arrived.
The suspect, identified as 45-year-old Ronald Kelly, suffered non-life-threatening injuries during the altercation and was transported by ambulance to Stony Brook University Hospital for treatment.
None of the employees were injured.
Kelly, of Holtsville, is charged with first-degree robbery and criminal possession of a controlled substance.
Police stress that they generally discourage victims from taking matters into their own hands, as in this incident.
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