Scion Murder Mystery

[Chronologist]

I'm currently running a Scion campaign, and the next session is going to be a murder mystery in an Atlantean ruin. All supernatural abilities are being suppressed inside (for various reasons).

The mystery is pretty basic. 4 suspects (1 missing somewhere in the ruin), 2 have motive, 3 have opportunity, the weapon is missing (but can be found), and through light investigation, interrogation, and technical knowledge everyone innocent can be ruled out (for multiple reasons, even).

My group likes tense, horror situations like this, but none of them are very good at puzzles (except maybe one of them). Unfortunately for them, the murderer plans to kill the players as well, and will be able to within a few hours of the first murder. It would most definitely mean TPK.

Is this okay? I don't want to create a Cake or Death situation here (there are 6 other possible outcomes), but I want the players to understand that death is a distinct possibility if they fail.

 

[Dannyalcatraz]

A couple of ideas:

1) Are there any NPCs along for the ride? If so, you can pick them off to establish the "ticking clock" of the adventure.

2) Are any of the players dissatisfied with their PCs? If so, approach that player with the option to have his PC be the "Black Guy" (a.k.a. "Redshirt") who dies to establish the seriousness of the situation. Then let him play another PC (perhaps one of the NPCs along for the ride is actually his new PC?) or help you run some of the NPCs as a "co-GM" of sorts.

 

[Chronologist]

Thanks for responding Dannyalcatraz.

1) There is on NPC in the group (with only 3 players I have to bolster their ranks somewhat) but she's pretty important to the story. She dies if they do, and there are two outcomes where she dies but the party lives, but I'd rather not kill off NPCs I've been carefully crafting for months on a one-of mission.

2) One of the players is heavily invested in his character, and intends to play her through the whole campaign. Another player just made a new character (death due to player incompetence) so killing him would be, well, unfair. The last player might go for that sort of thing, but I doubt it.

The killer has no reason to kill the players; the objective is to stall the players so the killer can adapt to the power-nullification field and kill everyone easily.