Okay, let's start off by saying this film is not an exact rendition of the crimes and legal pursuit of Andrei Chikatilo. While it may have been "official policy" in the Politburo that the USSR had no serial killers, in actuality the legal system had handled others, and "Killer X" (as he was actually called) was already being sought when Fetisov brought Burakov onto the case. In fact, as soon as it was realized they had multiple murders on their hands, the authorities assigned a task force of dozens of officers to track down and end the killing spree of a man that did not fit into what is perceived as normal serial killer parameters. It's good the director and writers consistently remind the viewer that the story is only "based upon actual events," for a docudrama this ain't.
***SPOILERS FOLLOW****
That said, this is a damn good example of a fast-paced Hollywood-style thriller that still gets across the basics of what happened. It is easy to follow and has just enough truth behind its version of events to make for compelling viewing. Yes, Chikatilo raped and murdered both children and adults, both male and female. Yes, shoddy lab-work set him free to continue killing for years. Yes, innocent men were accused of the murders and "confessed" to their crimes at police urging. Yes, the gay community was harassed while the crimes were being committed (albeit with Burakov's committed assistance). And yes, Chikatilo was brought to confession not by the haranguing of the special prosecutor, Gorbunov, but by the gentle understanding of a psychiatrist named Bukhanovsky (though Gorbunov was really nowhere near the egotistical martinet portrayed in this film). Quibbles about truth and veracity aside, all of these events are dramatized in a manner that consistently tightens the tension and fear.
It doesn't hurt that director and co-writer Chris Gerolmo has a pitch perfect cast. Stephen Rea's growing emotional involvement in the killings and developing expertise in detecting clues, Donald Sutherland's snarky manipulation of the Soviet party hacks and subtle spine that becomes evident when it is needed, Jeffrey DeMunn's seething undercurrent of rage hidden by a fear-filled demeanor, Max Von Sydow's boyish excitement at being part of a criminal investigation all enhance the sharp dialog and crisp editing in ways that cannot be underestimated.
Taken for what it is, "Citizen X" is almost pitch perfect (the "almost" due to one moment of self-congratulation at the end that just does NOT fit). Highly recommended as fiction well-told, not fact being presented...but considering the junky "serial killer" movies that Hollywood usually spits out, that's good enough for me.

note to George Litman, and others: the Mystery Science Theater 3000 riff is "I don't think so, *breeder*".
my favorite riff is "Why were you looking at his 'like'?", simply for the complete absurdity. that, and "Right well did not!" over all, I would say we must give credit to the MST3K crew for trying to ridicule this TV movie. you really can't make much fun of the dialog; Bill S was a good playwright. on the other hand, this production is so bad that even he would disown it. a junior high school drama club could do better.
I would recommend that you buy a book and read 'Hamlet'.