Flash Mobs Turn Violent, Become 'Flash Robs'

Flash mobs are usually associated with random dance numbers or large-scale pillow fights. They're organized over social media sites like Facebook and Twitter, and tell people where to be - like at a mall, a park, a coffee shop- and what to bring - such as a costume, boombox or sweet dance moves.

But recently, gangs have commandeered the innocent "flash mob" and turned it into a "flash rob." Social media is being used to organize groups of 50 to 100 young people that all descend on the same store or area and loot it.

Philadelphia, Pa. has been hit especially hard by this summer's "Flash Robs." So far there have been several injuries as a result of the violent robbing. The Police Department there has put in curfews for minors--with fines of up to $300 for the kids and $500 for their parents. The city is also extending hours at teen recreational centers, to help give kids something else to do.

We'll talk with the Philadelphia Police Commissioner about how his city is cracking down on large groups of teenagers, and what police in the UK may be able to learn from American law enforcement efforts.