I imagine you're in the district that's located at 55th and Pine, but you just need to call 911 and they'll take a preliminary report on the phone, and probably send an officer out to take a full report. It may seem futile, but it's worth doing. For one thing, they could possibly find your bike. Or they could get reports that suggest an organized ring of bike thieves. Or the accumulation of data can help them figure out their patrol routes. Or your report could have no effect at all. But it's worth taking the time.