[ siren ] >> there is a patrol officer. one minute you can be breaking up college party, and 20 minutes later, you could be shot called. >> the call was for shots fired in roxbury. >> anybody see anything? >> but with no witnesses, there is not much to go on. >> who knows to come up this way? >> i have no idea. they came up here to shoot. >> that's what i'm saying. who? >> sometimes you get to the scene, but nothing pans out. but what we try to do is try to be proactive. what's going on? were you there for that? >> no. i started running. >> generally speaking, that's the way you produce good results. >> all right. >> later. >> you too. >> it's another shift in dorchester for the night gang unit. two cars patrol the neighborhood in tandem.