Law enforcement officials frequently turn to Facebook to solve crimes or gather evidence. However, the victims of crimes themselves are also using the site to help catch perpetrators, like a 15-year-old New York boy did this week to identify his mugger.

On October 27, the victim had his wallet and cell phone snatched at a bust stop in Staten Island, New York. However, the victim thought he recognized the robber from around his neighborhood, and used Facebook to find him. The alleged mugger, 18-year-old Philip Joe, was arrested by police the very next day. (The accused criminal was already out on $10,000 bail for a robbery committed this summer.)

For police, collecting evidence of crimes has never been easier than it is on Facebook. (The penchant of many criminals to post photos and brag about their exploits certainly doesn’t hurt.) However, the ability for users on the site to effectively do detective work themselves gives the site an intriguing potential use as a tool for social justice. It could also open up new avenues of trouble for police, who likely don’t want citizens interfering with ongoing investigations.

Readers: if you suspected someone you knew of committing a crime, would you go to the police about it first or look into it yourself by snooping on Facebook and other social media?