The Ship is rather fun and I’d love an excuse to go back, but don’t think too highly of its murder mystery aspect. It’s chaotic fun and very clever but its nothing special in that specific regard.
Finding an actual murder mystery game would be interesting though. Have you guys played “Mafia” games before? They’re good slow games for forums when you have a very large and active community, but for smaller groups and casual players you can jump into EpicMafia which is a great replication of the game.