CHICAGO (CBS)—Hundreds of teenagers swarmed city streets for the second time in a week on Easter Sunday.
This time, police arrested 12 people who contributed to the mayhem that clogged parts of downtown.
Experts said the mobs aren't just disturbances caused by crowds of teens with nowhere to go. They're actually diversions to serve as a distraction so crimes can be committed.
Hundreds of teens crowded streets in Chicago's upscale River North neighborhood on Sunday. Some blocked streets and dodged in and out of traffic in an area stretching east near Lake Shore Drive.
Police on bikes yelled at the unruly kids to stop, but the mayhem continued.
Alderman Brian Hopkins of Chicago's 2nd Ward says pockets of violence sometimes erupt within the mobs.
"There's violence that's associated with these large groups that really isn't reported," Hopkins said.
He continued, "People are getting hurt. They're being struck. Punched in the face. Older people are getting pushed to the ground. Purses are being stolen."
Hopkins said groups of teens connect on social media and make plans to bombard downtown areas together.
"Some of the organizers on social media are doing this intentionally," Hopkins said. "They're trying to get large groups together so they can hide behind these groups and commit these criminal acts."
Hopkins said retail theft in particular spikes during these incidents because the police are spread thin and store security guards get distracted with the large crowds.
"They basically turn their backs on the merchandise so the next thing you know, huge amounts are going out of the store," Hopkins said.
Dozens of anti-theft devices were said to have been discarded near the Magnificent Mile after Sunday's mob scene dissipated.
Chicago police said patrols are being increased to help prevent mobs from coming together.
The teenagers arrested Sunday have since been released to their parents, police say.
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