Most likely they were two confused fans. Just because fan of some artist kills someone doesnt mean that it is that artist to blame.
Beatles's song "Helter Skelter" had supposetly inspired Charlie Manson murders... so Beatles are evil too?
Show me ANY Manson lyrics where he tells people to kill in the name of devil. Please. Here's even lyrics site for ya:
http://www.azlyrics.com/m/marilyn.html