CHICAGO (CBS) — A knife-wielding man died of a heart attack Sunday, after stabbing two people at a store in a strip mall in Gary, Indiana.

Police said officers responded to a fight inside a store on the 5000 block of East Dunes Highway in Gary around 3:30 p.m. Sunday.

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A 34-year-old man had become agitated inside the store, and taken a kitchen knife out of a display, and attacked a 60-year-old man at the counter, according to police. The man with the knife then attacked a 19-year-old employee who tried to stop him.

Two other employees tackled the man when he began threatening other customers. While the employees were holding him down, the started suffering shortness of breath, and the employees started performing CPR.

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When police and firefighters arrived, they took over performing CPR, and took the man and the two stabbing victims to Methodist Hospital Northlake.

The man with the knife was pronounced dead at the hospital, after suffering an apparent heart attack. The two stabbing victims were treated for knife wounds.

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Police said the attack was recorded on surveillance video.