SEE IT: Washington Heights robber stabs teenager in apartment building lobby

The NYPD released disturbing video footage Friday night of a knife-wielding Washington Heights robber who stabbed an 18-year-old man in an apartment building lobby earlier this month.

Police said the incident happened at about 7:35 p.m. on Aug. 17 inside 86 Fort Washington Ave.

According to law enforcement sources, the crook approached the victim inside a staircase, then displayed a knife and demanded property.

That led to a physical struggle between the robber and victim in the lobby, caught on camera. Authorities said the suspect stabbed the victim six times about the body while stealing his backpack, which contained his wallet and keys.

Police said the perpetrator then fled the scene on foot, and was last seen heading southbound on Fort Washington Avenue.

The incident was reported to the 33rd Precinct. Police said the victim was taken by private means to NewYork-Presbyterian/Columbia University Irving Medical Center, where he was listed in stable condition.

As shown in the video, the suspect wore a dark gray t-shirt with a Levi’s logo on the front and was seen carrying a black backpack.

Anyone with information regarding the robbery can call Crime Stoppers at 800-577-TIPS (for Spanish, dial 888-57-PISTA). You can also submit tips online at crimestoppers.nypdonline.org, or on Twitter @NYPDTips. All calls and messages are kept confidential.