Police Intervention

I was having my lunchbreak walk yesterday when I suddenly heard sirens screaming. Then I saw two police cars, all lights blazing, going down the road to an unknown location. I think they were going to a dodgy area of the town where I work, which has its share of dodgy areas, come to think of it. I checked online later, I found nothing about any police operation. Were they going on a raid? A drug bust? Probably answering to some emergency call, thus the sirens, but what, I could not find. In any case, this brief sight got my imagination running, as it often is when I see a police car with sirens and emergency lights on. I always wonder where they are going and why. It's a good starting point as any for a crime story.