The incidents happened Thursday night at the Central Avenue Station in Bushwick.
Police say the suspect was on a southbound M train when he demanded $10 from a female victim while displaying a needle. After she handed over the money, he grabbed her inappropriately and fled.
A few moments earlier, authorities say the same suspect threatened and demanded money from a male rider.
There were no injuries in either incident.
Anyone with information in regard to this incident is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). The public can also submit their tips by logging onto the Crime Stoppers website at WWW.NYPDCRIMESTOPPERS.COM, or on Twitter @NYPDTips.
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