I am trying to come up with a good murder mystery plot that my party can cover over three sessions. The murder, in typical Dresden fashion, could not have been done by a human so the party investigates to see what sort of fairy or demon or rogue spellcaster did it.
Since I watch a lot of TV I figure session one is crime scene investigation and interview witness, session two is tracking down the bad guy, and session 3 is the big showdown. My problem with that plan is that there is absolutely no mystery or surprise involved.
How do I get a good mystery for an adventure without railroading the party?