For the long shot, I'm betting on Green. He's from Global Order, so we know he belongs to an organization dedicated to eradicating rogue mages like Infinite, he's been very mousey about his purpose here, and he's nowhere to be seen in this chapter.
I think less eradicating.. more just countering. The main goal seems to prevent them from doing as they please and creating chaos.
And i can see why someone might guess Mr Green is secretly a GO assasin. But infinity joined on very short notice.
So i find it unlikely Mr Green is someone send after Infinity. More likely he is there of his own reasons.

I'm putting my money on Bindy. Here's my reasoning:
Not an unreasonable guess. For a significant amount of murders the victim did know his killer.

Tobi time
A trivia quiz?
Turns out its a world building overdose :P
Well we got a lot of interesting information. Like what caused the fall of the GO founder.
Whats the major GO political parties. Who are then 10 most wanted criminals.