Has there ever been a murder-mystery event? Like modmins prefabricate a crime scene, write up stories to give to players that are "witnesses" and so on. It sounds like something that SS13 would be suited to, but taking away the bit where people mash the arrow keys clicking desperately to do the murdering.
That sounds awesome, but it might need to be paired with some other, smaller events, since it'd probably get boring quickly for anyone not in Sec. Maybe the murderer is tasked with disrupting station life, like a traitor with less resources? Or maybe they need to arrange some unfortunate accidents for other members of the crew? For some extra spice, maybe the Evacuation Shuttle isn't available for whatever reason, meaning the crew need to either root out the murderer or die.
I may try something like that soon.
Oh, I have an idea how to pull that off, albeit one that only works as a gamemode proper.
Clue(do) style: a murder weapon and pieces of evidence - mostly papers with messages implicating various crewmembers - are scattered around the map. The modules of a possible motive to kill the victim (possibly an NPC Captain, would take up the job slot) would be assigned to a crewmembers and added to their medical/security/employment notes and one person would be assigned as the real killer; a small percentage of the evidence would be picked as red herrings, pointing towards the innocents.
The killer would get an antag message of 'you've blacked out, but you realize you've done something horrible, you must find the evidence pointing towards you!', gets a 0 TC syndie uplink for secret records and learns what the murder weapon was, so both sides have to do a scavenger hunt for the evidence, but good guys have to analyze the crime scene first to get a lead on the weapon, so they are at a slight handicap. Since the data about the suspects is hidden away in different personnel files, you have to get the cooperation of Sec, Med and a Head (for employment records) and there might be a killer in any of those, trying to derail the investigation.
The killer may try either to destroy the evidence - dumping the murder weapon and burning the papers with fire or acid or wiping them clean with alcohol (already possible, fun fact), or keep them if they are red herrings for a high-risk high-reward play of blackmailing someone into helping him.
The normal crewmembers are also invested in the investigation (pun not intended), since an investigation gone bad means they are the ones who get - innocently - arrested for the murder.
It's definitely doable (not sure how adding to notes would work, but it's probably doable as well), although it would require setting up the map to have potential evidence-spawning spots and some writership for the motives although a placeholder system would work beforehand.