The 37-year-old man and the 33-year-old woman got into an argument with the belligerent suspect on board a northbound 4 train at the Bowling Green Station, according to cops. The suspect then followed the couple as they got off at the East 170 Street and Jerome Avenue train station.
At that point, the suspect punched the man in the back of the head and stabbed him. The wife attempted to intervene when the suspect pushed her down the stairs, said cops.
The couple was taken to Lincoln Hospital in stable condition.
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Police want to find the suspect described as a male with a dark complexion, approximately 30-years-old, 5'11" tall, weighing 180 pounds. He was last seen wearing a black Nike baseball hat, a blue face mask, a gray hooded sweatshirt, black pants, black sneakers with a black backpack.
Video released by police of the assault on April 27 at about 7:44 p.m. shows the suspect following the incident.
If you recognize him, call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477). The public can also submit their tips by logging onto the Crime Stoppers website at WWW.NYPDCRIMESTOPPERS.COM, or on Twitter @NYPDTips.
Cops say all calls are strictly confidential.