The vigilantes in this episode get a few different nicknames within the show. "Justice League" is a nod to DC Comics' superhero team, the Justice League, and "masked avenger" is a nod to Marvel Comics' superhero team "the Avengers"
The reporter in this episode is called Dennis Griscomb. On Law & Order: Criminal Intent, The Third Horseman [season 1/ 11], the main character is also named Dennis Griscomb.
One of the witnesses is named Stuart and owns a comic book store. In the sitcom The Big Bang Theory, Stuart (Kevin Sussman) owns a comic book store.