The cops only have their eyes on Uruma. Every other crook in the city is free to do whatever they want. I mean, this random judo club member just confession to burning a house, possibly costing over 10 million yen considering it would have been full of stuff, which he would need to spend much of his life paying for, unless his parents are rich and do it for him. Normally you'd go to the police if some brute tried to blackmail you to do that, but since every single cop in that city is only after Uruma (and not very good at that, either), the place is basically a lawless jungle.