And this is how they act when talking about a dead body.
MULDER: So he was murdered.
SCULLY: Well, no. As far as I can tell this man died of advanced coronary disease.
MULDER: Natural causes.
SCULLY: Yeah.
MULDER: So, basically he died of a heart attack, somebody crept up behind him, sawed his head off and then glued it back on all in the space of 30 seconds. Does that make sense to you?
SCULLY: No. Which makes it even stranger still because, as far as I can tell this body has been dead for over a month. I see signs of refrigeration.