NEW YORK (CBSNewYork) – The NYPD wants your help finding a suspect in a string of subway cell phone robberies.

Police believe Richard Brown, 21, carried out five robberies since August, targeting riders of the F, A and J trains.

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All of the robberies took place in the subway system and follow a similar pattern, according to police. Brown approaches victims typically during early morning hours, starts conversations with them, and then usually tells them he has a gun and demands their phone, police said. The robberies took place on the platform and on the train. Brown is suspected of carrying out two of the robberies on Sept. 20, with another person acting as lookout.

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Brown is 21, 5’10”, about 160 pounds with tattoos on his face, neck and hand, police said.

Anyone with any information is asked to call NYPD Crime Stoppers at 1-800-577-TIPS (8477). You can also submit a tip via the Crime Stoppers website, or by texting a tip to 274637 (CRIMES) and then entering TIP577.

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All calls are kept confidential.