Just like police often have informants in gangs, I predict that they have the same in some of N Idaho's extremist groups. People that may revel in rhetoric, but haven't yet done anything particularly illegal and would turn in vicious killers, just to keep focus off them.
I voiced my opinion from the start that imo it is a local, begrudging of one or all of the victims because of "free" lifestyle, possibly rejected in a bar where he hung out to "watch". He loves his knife, most likely had a cool sheath that bar patrons may recognize, maybe shows up on bar videos. Is practiced in butchering game. Would fit in any isolated rural area, but the extremist groups would be more aware of his fervent attitudes towards richie rich students, (in his opinion).
Imo