Tiimwork (Othello) was an investigator and did everything he could to confuse the town and make them lose. He claimed invest (which turned out to be true), but he never helped the town with any info. As soon as there was irrefutable evidence who was left in the mafia (sheriff died and left a last will, GF was detectable too), he started helping the mafia lynch off the other two remaining town members (myself the vigi and orange the doc) even though the mafia could get no more kills at night. Town would have had a guaranteed win with 3v2, but Othello proceded messing things up. He finished the game with the words "all hail to the GF" or some nonsense when he got lynched.
I'm not sure if he might have been skyping with someone on the mafia - our complaints on the death chat were met with a QQ more from a mafia player who died early - but he was definitely trolling.
I'll attach a replay file as proof.
EDIT: Forgot to add he began the game with a random lynch of our doctor. And when he found the GF (leader among men), he framed a guy who had just disconnected, saying that he was GF instead.