Мафия 32. Asylum

I'm curious, what makes these psychos willing to cooperate? They killed Arandor – it seems no one disputes that. And according to the reasoning and the newspaper headline, Arandor was the main doctor-killer. But didn't the psychos know that beforehand? It could just as easily have been the murder of a city official. Why is Gil calling for the investigation to be put on hold until more evidence is found?
(I'm going to start digging into this right now, just on principle)