BROOKLYN - An advocacy group doubled its offered reward Thursday for information leading to the arrest of the suspect in a knife attack that injured a Jewish man.

Police say someone stabbed the 25-year-old victim in the back outside 646 Empire Blvd. in Crown Heights. Surveillance video shows the apparent suspect fleeing the scene on foot.

The victim's lung collapsed as a result of the assault, but he is recovering at Kings County Hospital, according to officials.

Police designated the attack a hate crime.

The Anti-Defamation League is offering a $10,000 reward.