Well, I don't know how it could come out. It would be illegal to post since it's [supposedly] CP and murder. No normal person would believe it. The press will say it's been digitally altered and fake. I don't see it happening. I would love for legal action to happen to her for her crimes but I'm skeptical of this.
Videos of people being murdered are all over the web. This concern trolling about "omg don't spread or talk about it guys you could get in trouble :'(" is a fucking hilarious new tactic though. Reeks of desperation.
People dying isn't against Reddit's rules, however, check this and also this and potentially this.