One problem is the lack of motive to murder, if people play strategically to win everyone would probably play it safe. Maybe a GM sends a message telling the murderer to kill someone of their choice and the murderer responds with the victim, location and weapon of choice. Then the GM posts on the IC making an announcement that [i](Victim) has been murdered! They were killed at (Location) with a (Weapon)[/i] and PMs the victim telling them the murderer and the victim responds to the GM with more evidence, but if the GM decides the evidence is too obvious they get the victim to change it.