The shooting happened shortly after 6 p.m. Saturday at La Vaquita Deli on Great Neck Road in Copiague.
One of the victims is in critical condition, and two others are in serious condition.
No arrests have been made, and the investigation is ongoing.
There is no word on what led up to the shooting.
Anyone with information is asked to contact Crime Stoppers at 1-800-220-TIPS.
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