Trying to find mention in the press but can't find anything.

I was on a rooftop last night. Shortly after the fireworks ended nearly a dozen motorcycle cops came blaring down Randolph. At first I thought they were escorting a dignitary. When the spotlight copter came in, it became clear they were after somebody/somebodies. A herd of men, and assume-ably panicked bystanders, ran through the parking lot at Randolph and Lafayette. The officers stopped, circled and searched. And that was that. Anyone hear anything?