The X-Files Season 9 Episode 8

Dr Mueller: In all my days, I never saw anything as inhuman as this. (He's looking through the case file and autopsy photos)
Scully: Sir, I haven't located police records from the investigation. Was there ever a suspect who was charged or arrested in this case as far as you know?
Dr Mueller: No suspects, no investigation for that matter.
Scully: I don't understand.
Dr Mueller: The victim was a John Doe — a nobody. Carl Hobart, the county sheriff, figured he was a drifter. Hobart said he didn't want to stir up the community.
Scully: And no one called him on that?
Dr Mueller: I tried... the sheriff had other things on his mind, I suppose.
Scully: Why do you say that?
Dr Mueller: Well, it wasn't long after that he put a bullet through his head. What are you thinking, doctor? This is some copycat murder 40-odd years later?
Scully: If so, it's the most perfectly executed that I've ever seen. And why copy an obscure murder that nobody's ever even heard of?
Dr Mueller: A string of murders.
Scully: I'm sorry?
Dr Mueller: I thought you knew. John Doe... was only the first.