Surveillance video shows the suspect in the vicinity following the incident on Westchester Avenue in Soundview.
Police say the man walked up to the victim, who was trying to make a deposit, and demanded money.
The suspect then Tasered the 50-year-old victim in the arm, grabbed $20, and fled.
Police are asking for the public's help tracking down the suspect.
Call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). You can also submit tips by visiting the CrimeStoppers website at crimestoppers.nypdonline.org or by messaging on Twitter @NYPDTips.
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