My setting is London during the industrial revolution with fantasy elements and I've got the PC's in an apartment where there's been a murder. There's these two brothers, one an assassin and the other an illusionist, and they're trying to frame the PC's for murder. There's two that would be easier to frame (minor criminals), and two more who are basically investigators. My plan right now is to have the baddies try to take the two investigator PC's out of the picture while framing the other two.
So the assassin killed guy A who lives in the building and used a hat of disguise to replace him, then murdered dude B at the building. They're sort of investigating that murder right now, which is the distraction while I try to frame them for that and maybe more murders? The body of guy A is on the roof in a bin.
tldr; how best frame PC's for muder in a modern/fantasy setting?
(images are all stuff I made for the game)