It is revealed that Mulder is red/green color blind.
The informant who tells Mulder about the case should have been Steven Williams in his role as X. However, due to Williams' concurrent role L.A. Heat (1996), scheduling conflicts occurred so Tim Henry filled the role.
The final two scenes take place on May 10, 1996. This was the same day that this episode originally aired.
The name John Gillnitz shows up at least six times in the series, usually as a throwaway character. It's an in-joke. The name is an amalgamation of the names of three people who worked on the show: JOHN Shiban, Vince GILLigan and Frank SpotNITZ. The John Gillnitz name appears in this episode as the victim in hammock (actor uncredited), Leonard Betts (1997) as the bearded man/murder victim (actor Ken Jones, uncredited), Christmas Carol (1997) as the DNA technician (actor uncredited), Dreamland II (1998) in Gillnitz name is only mentioned and the character does not appear on screen, Theef (2000) as Reporter 2 (actor Mark Thompson), and Jump the Shark (2002) as man with bio-weapon (Marcus Giamatti).