Bring Sigmund to Justice

The Stormbound Alliance have offered us 350 gold pieces to capture the gang leader Sigmund and bring him to justice. We can get the full 350gp if we bring him in alive, but they won't mind too much if we have to bring him in dead. In addition, our ally Nardelian Frostcrow has added an extra 75gp to the bounty, as he is tired of Sigmund's gang attacking his cargo ships.   We interrogated some of his goons under a Zone of Truth. They told us that Sigmund's higher-ups hang out in the Old Concert Hall down by the waterfront. Maybe it's time to head there and start asking questions...