"Traitor" role in deduction game, possible?

Ability to lie about clues.

No, because if caught in the lie the traitor will lose. The traitor must hide his identity without hiding it in a provably false way. If the traitor doesn't know what the other players already know, there is a possibility that he will fall into this trap.

Check out this game : London 1888

http://www.boardgamegeek.com/game/19991

I have played, it is really nice. Basicaly each player has 5 hidden cards, when interrogating the interrogator reveal a card. If it is a "false track", the card is removed, a suspect, the player card are reshuffled and and identity determine that you are either innocent or "jack the ripper".

Now there are many victory condition. ( I don't remember all of them )

- If jack is never revevealed, he wins.
- If jack is never cought before the last event, he wins
- if jack kill all the other opposing players, he win ( some character's support jack )
- Jack can always try to hang himself at his house if he has the rope. Doing so makes him win since nobody know who is "Jack the ripper"
- Capturing or killing jack will make the other player(good guys) wins.

Deception, a game for 5 or more players. (5 sounds good... I'm just making this up as I go)

Description: Each player controls a killer and a few innocent people.

Setup: Separate the red and black suits in a deck of cards. The red deck represents living, breathing people, some of whom are serial killers. Deal this deck out face down to each player.

Each player then secretly draws a black card. This card reveals their killer's identity - Hearts matches with spades, diamonds matches with clubs (i.e., if the drawn card is the 4 of spades, the killer is the 4 of hearts.) Players must memorize it, set it aside, and may not pick it up.

Now, the rest of the black cards are dealt out to everyone these represent alibis for the innocent people. Red = people, black = alibis... hearts -> spades, diamonds-> clubs.

You might not have the red card that matches your killer card. This is OK.

Goal: Be the last killer standing.

Play: There are two cycles to play: day and night.
During the Day, Someone gets lynched. Each player puts one red card from their hand into the center. Players then argue and fight about which red card gets killed. It is a wise idea that if someone else plays your killer's red card to make sure it doesn't get killed. But don't be too obvious about it.

Players must decide vote on what red card gets killed. Once that is determined, then proceed.

If you have the alibi for the red card that is lynched, put it down. If the red card has no alibi, then one of the killers was taken out. The player owning that killer must reveal their card. They may no longer take part in night-time killings, but they continue to play.

During the night, an innocent gets killed. One player puts down a black alibi card. The player owning the matching red citizen card must lay it down. Those cards are discarded. Only one player kills per night, and this cycle goes clockwise, starting from the dealer. Skip players who's killer was killed.

Perhaps a third stage (investigation?) would be desireable, where players trade alibi cards (pass to the left or something)?

Winning:
Once every other killer has been eliminated, the remaining player reveals their killer's identity (the black card face down in front of them). Maybe a point system should be involved here. I don't know.

What do you think?

In my game Malice Aforethought, the players are all trying to become the murderer in the first phase. After a body hits the floor, the players switch to deduction mode, while the murderer tries to cover their tracks. The player's aren't safe, however, as the killer can, if need be, keep killing. But there is good reason not to do so, as each hidden action leaves clues that are very hard to clean up later.

Malice Aforethought was a very difficult game to create, as my design goals were to have a deduction game where the killer gets to kill another character during the game, in full view of the other players, and still have nobody know for sure who did it, thus leading to the second phase of the game. Trying to solve a murder with the killer still on the grounds is a much more tense affair than a bunch of detectives running around. suddenly, everyone's looking for weapons, and not just for clues...

Yeah, well, the hardest part about this sort of thing is to control the player's actions through some sort of believable rationale. In my game, it's the story: The group is initially in one room (the Library, or course), and have gathered at the behest of the house's rich owner (some sort of philanthropist, of course). Each has a motive for killing one of the other players, and each intends to do so. Well, the philanthropist has a heart attack before anyone can pull off their crime, and the lights have gone out due to a winter storm. The players split up to search the house and grounds for the things they need to save the man's life.

This, they all think, is my opportunity...

While collecting the objects their stricken host requires, the players are also collecting weapons with which to bump off their target. When someone succeeds, the quest to restore communications is started in earnest. Everyone else now knows that they dare not kill their target tonight, because their taget is now on guard.

The non-killers search the premises, finding clues as they do so. The murderer tries to find these clues as well... to eliminate them. Finding clues is dangerous. Not finding them is worse. If the killer can reactivate the phones and electricity, and make the call to the police, they'll establish their own alibi first, and get away with murder.

As you can see, the pre-mortem and post-mortem phases of the game are similar, and have identical mechanics, but the story effectively forbids all but one player from further killing. This makes the game very tense, as does the fact that the murder took place in plain sight, in front of all the players. Suddenly, one of them is attacked, seemingly out of nowhere, fails to defend themselves, and dies a horrible death. The others seem to look on innocently. Emphasis on seem.

This is not easy to pull off in a game, and Vegas-style casino busters may have an edge. But even knowing who killed the victim is useless if you can't prove it. And once a player kills once, it's foolish to let that person know you're onto them, as they have little to lose in killing again...