A dead criminal has already lost, they have no reason to care about the rest of the team, this is true.
Problem is, it's a yes or no.
If they answer yes, you try to get both of them killed.
If they answer no, you ignore both of them.
If you aren't actually the medium, then a claimed answer of yes, gives you an excuse to try to get both of them killed, and you can blame somebody who's out of the game.
If you aren't actually the medium, then a claimed answer of no, gives you an excuse to pretend that those two are checked, and safe.
I see four possibilities.
I also see that yesterday, gpuz made a claim that got the strongman killed.
I see that as a very strong lead to follow, he got lied to, and we can trace it back to find out from whom and make them pay.