It was an interesting albeit lengthy experience to organise. I had to create a sequence of events, scene of murder, suspect motives and make the mystery convoluted yet logical. The players would try to get as many clues as they could before determining and blaming their prime suspect.
Here's what happened:
WHAT ACTUALLY HAPPENED
By the end of the session, the players were stumped with each having their thoughts as to who the second murderer was. Having decided to give up and defer the investigation to the Arbites the session ended (past midnight, mind you!). Had any of six players had knowledge about the Ecclesiarchy they would have realised that the Confessor was dribbling made up crap. Here is the sequence of events, detailing how the murders occurred: