Video of the assault from Sept. 21 at about 2:20 p.m. was released by police. It showed the man approach the 76-year-old victim from behind and wrap his arms around his neck and head.
The suspect had followed the victim into the vestibule of an apartment building on Adam Clayton Powell Jr. Boulevard and West 129th Street where he assaulted him.
The victim suffered neck and ankle pain but refused medical attention, according to cops.
Anyone with information about the assault was asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477). The public can also submit their tips by logging onto the CrimeStoppers website at WWW.NYPDCRIMESTOPPERS.COM, on Twitter @NYPDTips.
All calls are strictly confidential, say cops.