The Thirteenth Chair (Unabridged)

Your best friend has been murdered, stabbed in the back, and the police haven't been able to solve the case. You have consulted with the best detective in the area. You have asked friends and neighbors about the crime. You have even offered a very generous reward, without result. How far would you go for to solve the murder of the chap who saved your life? Would you lock yourself in a dark room with your friends for a seance while sitting in the thirteenth chair knowing that one of them is probably the murderer? -