Security camera video captured the assault near Southern Boulevard and East 185th Street in the Belmont section around 6:45 a.m. back on April 10.
The suspect, who can be seen holding something in one hand, swings at the 71-year-old man from behind with his other hand.
He was struck in the face and fell to the ground.
The victim suffered a cut to his face and was treated at NYC Health and Hospitals/Lincoln.
Police say the punch was thrown after the victim and the suspect got into some kind of verbal dispute.
The suspect was last seen walking on East 187th Street.
He is described as a male, Hispanic, 25 to 30 years old; last seen wearing dark-colored clothing.
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).
You can also submit their tips by logging onto the CrimeStoppers website at WWW.NYPDCRIMESTOPPERS.COM or on Twitter @NYPDTips.
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