Mafia 90. The Tale of Oldforest.

Okay, then, explain why Olam is worse. Judging based on behavior is completely stupid! But justifying based on behavior is even more stupid.

Judging based on behavior isn't stupid at all; if you knew how many mafia members reveal themselves through their behavior, you wouldn't say that. Even on "flood day" or "zero day" (the day for getting to know each other), many mafia members somehow manage to expose themselves. I'm not justifying based on behavior, but on observations. So, I'll repeat: in 90% of cases, the mafia doesn't rush to vote first. They don't need extra attention. It's easier to quietly distribute votes, one vote for one candidate, another vote for another, and a third vote for a neutral or completely random candidate. Well, this is just an example; if there are more mafia members, there are more options.

Added 2 minutes later

If we hang the cop, we risk hanging the only role capable of dealing with the serial killer.

If that's really the role, then the serial killer could be among those who want him hanged. The serial killer isn't risking anything; it doesn't matter who gets hanged, so eliminating the biggest threat is a good thing. One problem less. If it doesn't work, then there's still information.