first, I wanna say the reason I suspect mango is that she always ask ppl to vote xiaoyuyue. I think she wants her die without being investigated by police.　

Then you said you are police and mango is a citizen ..which surprised me!

now that I agree with you xiaoyuyue is not killer.. Then let's vote 331 or trueif.　

331 is very suspicious because he always agree with you or me without any suitable reason.

You know only killer knows that other guy is good or not. He can easily say you are a good man.that is always correct