NEW YORK - Police have released surveillance video of the suspect in a stabbing on the D train early Monday morning. 

Police say it happened just before 2:30 a.m. on the southbound D train near the Rockefeller Plaza station. 

Police say the suspect was harassing passengers on the train. A 27-year-old man tried to intervene, and was stabbed in the stomach with a pocket knife.

The victim was taken to the hospital and was expected to survive. 

Anyone with any information 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 a tip via their website or via DM on Twitter, @NYPDTips. All calls are kept confidential.