"None of us really knew anything about the murder except that we think was up at the tower...."
Well, let's start there, then. You take your crew around town in a couple of smaller groups. Just listen to people and watch. You'll be much better at blending in than I would be. See if you see anything odd or overhear anything. Don't engage anyone though - we don't want to get anyone hurt! Let's meet back here in two hours. I'll head up to the tower and see who I can talk to.
Once the kids are ready to go, I head towards the tower trying to catch the gaze of any militia folks. If I come across anyone with any authority...
Hello good sir, as a Knight of the holy Order of the Aster, I would like to offer my hand in helping you restore peace to this town. How may I be of service?
If I don't come across anyone high enough, I'll just keep going to the tower.