The title figure of Errol Morris' documentary Mr. Death: The Rise and Fall of Fred A. Leuchter, Jr. is a nebbishy Boston engineer who looks, at first, like he should be selling sundaes from behind a 1950s soda-shop counter. Fred Leuchter has a bulbous nose, a gleaming high forehead, and a pair of middle-age frown lines that frame his face like officious parentheses. He is hardly anyone's idea of the life of the party, yet when Leuchter speaks, in his caustic New England whine, the words have more spunk and authority than you expect. He's a geek who's utterly sure of himself, especially when he's discussing his career as a creator of superior capital-punishment devices -- electric chairs, chemical-injection timers, whatever it takes to execute condemned prisoners with as little fuss as possible.
Over the last two decades, in movies like Gates of Heaven and Fast, Cheap & Out of Control, Morris has developed the most merciless camera eye of any nonfiction filmmaker. He stares at his subjects as if they were wriggling insects, and Fred Leuchter, with his worrywart face looming before us like one of the oversize heads in a Chuck Close painting, is no exception. Here, though, for the first time since The Thin Blue Line, Morris' charged interrogation-room technique results in more than an absurdist jape. Employing a hypnotic jump-cut style that appears heavily influenced by Oliver Stone's Nixon, he creates a kind of instant X-ray psychoanalysis, fixating on Leuchter's creepy mechanistic indifference in a way that allows us to fixate on what it's camouflaging: Leuchter's infatuation with death, and with his own power over it. In a minor but revelatory detail, Leuchter confesses, rather proudly, that he drinks 40 cups of coffee a day. That's not just overstimulation it's heavy drugs. In Mr. Death, this designer of ''humane'' killing machines is revealed to be a bureaucratic mortality junkie, perhaps the most passive-aggressive man of the 20th century.
Just when you're certain that you've got the rat fink pinned, the movie takes an astonishing turn. It follows Leuchter as he's tapped, in 1988, by a neo-Nazi Holocaust denier on trial in Canada (where the spreading of ''false news'' was, at the time, a crime) to do a study debunking the reality of the gas chambers at Auschwitz. In extraordinary video footage, we see Leuchter in the death camp, chipping and scraping away at the 50-year-old extermination-room walls for evidence of cyanide; he's like Poindexter in the Temple of Doom. When his samples yield no poison, he concludes that the atrocities didn't happen, and he becomes a star on the Holocaust-denial lecture circuit. Fred Leuchter is just one deluded figure, but by the end of this great and chilling sick-joke documentary he stands as a living icon of the banality of evil, a man who blanks out the world around him, replacing it with his own ego, always denying his desire to annihilate. A