Lost a Firefly themed ninth game of Mafia to a Serial Killer victory. I was Kaylee, a naive cop, and did correctly guess Night 1 that I was unlikely to be accurate; but when Mal was revealed to also be a cop, I figured he was more likely to be insane than for Kaylee to be naive. Ironically, it was moot: my targets were all innocent, at least at the time of investigation: I did investigate the SK who eventually won on a night when he’d have been revealed as innocent anyway.
While I did misplay, it doesn’t seem that any of my mistakes were direct causes of the town’s loss, though they indirectly might have made things complicated enough to be considered contributory to the loss. Interestingly, half of the lynches were correct, including the final 2.