@CA: This was at least 3 years ago now and I played it only twice but I played a game called 'Mafia' that is effectively Serial Killer.
One spy, one killer, one medic, the rest are victims plus the game master. Game master provides narration and alerts players to events.
We all sit around a table and deal out cards. The players read their card then close their eyes. The GM sees each card, picks the largest value and that's the killer. Reshuffle, largest value for medic, etc.
The GM starts the narration and on cue players close their eyes. A tap on the back means you're the killer, two taps the spy, three taps the medic. The killer then looks up and around and points at who the victim is. The medic is then told by the GM to pick someone to save. On the third turn (or even shorter into the game, depending on the number of people playing) the spy gets a chance to point at a player to ask if that's the killer. The GM must tell him if he gets it right.
The narrator tells everyone to get up except _____ who died because of _______.
From then on the mob must decide who to lynch and someone has to die. If you die you get to watch what happens when everyone closes their eyes but you cannot provide any clues or speak.
So yeah, Serial Killer.
This doesn't take a long time to do, the longest game I was in took an hour tops.
[sub]I was lynched the first time for 'being new and therefore evil' according to my friend James. He later turned out to be the killer.[/sub]