For connoisseurs of repellent cinema, there's never been a psycho thriller as insidiously skin-crawling as Michael Powell's portrait of a would-be director as a serial killer. (Brian De Palma took the back story to this film and made it the plot of "Raising Cain.") Carl Boehm plays the title creep, a focus-puller at a London movie studio who moonlights as a pornographic still-photographer and spends his spare time shooting a documentary about murder, starring his victims. Boehm's father, played by Powell, was a celebrated biologist who wanted to chart every stage of human development and specialized in "fear and the nervous system." While using a 16mm camera to document his son's growth, he went to fanatic extremes, even scaring him awake with a lizard so he could study the boy's hysterical reaction. Boehm extends this line of research: he turns the third leg of his tripod into a bayonet, and films his female targets as they die in a state of excruciating fright. The movie has its witty moments -- a shrink notes that Boehm "has his father's eyes." But "Peeping Tom" isn't a black comedy. It's an obsessive-compulsive nightmare.