A family says an E train rider threatened them with a knife and said the husband was "going to die today" after they told him to stop hitting his child. Now the police are looking for the suspect, who is wanted for menacing.

The incident took place on June 24th around 3:30 p.m., on a northbound E train as it approached West 4th Street. According to the NYPD, the suspect had been slapping a child in a stroller, prompting the other riders—a man and a woman who were with their daughter—to intervene and tell him to stop. The man responded by screaming profanities at the family, and by the time the train arrived at West 4th Street, he was allegedly wielding a knife and holding the train's door open as he threatened the husband.

In an interview with NBC NY, the family said that no one else on the train said anything about the man slapping his small child except for them.

Speaking with WABC 7, the father recalled, "He hit his child on the arm and because it was silent at that time so everybody could hear the noise he hit his child so hard." When he and his wife tried to intervene, the the man allegedly shouted, "Come do something! I will kill you. I want you to do something."

WABC 7 has more on the video, with audio:

When the family's 4-year-old daughter asked if everything was going to be okay, the family says the suspect told her, "Your daddy's going to die today."

The NYPD describes the suspect as being in his 20s and last seen wearing a red T-shirt.

Anyone with information in regards 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 by texting their tips to 274637 (CRIMES) then enter TIP577.