I feel like you could just have people get guns legally, not get any finger prints on them, dispose of them obviously and just have the gun connected to the framed individual. Pretty sure if they confessed not much else would happen. The only hard part would be getting away from the crime scene.
Framed individual having a solid alibi would screw you over and at most they'd be charged with some sort of negligence for their firearm since that shit is supposed to be in a locked location/cabinet. Confession would still be vetted for spree and serial killers. If it was a single homicide with clear evidence maybe that's all it would take, but i don't think that would apply to multiple murders.
You could drop DNA in any way, get recorded through a camera leaving the scene and it would simply be better to not kill anyone Chapo. I think five guys might actually fire you for that.
I bet I would get my job back when I got out. You’d definitely have to be sure that the people you frame would not fuck you over.