The bartender has a tip for you: he suggests you check a certain warehouse for the proof you're looking for.
You will be in a warehouse and will have to look for a specific crate (by clicking on them). The guards are level 4, and once you have found what you're looking for, two more of them will spawn at the exit point.
- Find Some Evidence
- Get to the Escape point
Return to the Town Magistrate when done. He'll tell you to go back to the Bartender for the follow-up mission.