Is not even the guild that is investigating him, is the equivalent of the church knights that hold more power than the adventurer guild and they can't interfere, which the spy girl is part of, so capturing, killing, punishing, etc the guy now or earlier, is throwing off the lead they have for the bigger criminal organization he is part of (since he is really dumb and easy to follow), so they have to deal with him for now, it just add to his crimes, but the pay off still happen, but will be way off still, since we're starting the 2nd arc and that won't happen until the end of it