The NYPD released a sketch of one of the suspects.
They say the phony officers ask the victims to see their ID, and then they snatch their wallets and run away.
Police also released video of a four-door sedan believed to be their getaway car.
Investigators say the suspects struck at least three times, all during the month of July.
Anyone with information is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).
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