Serial killers are fascinating; their acts are repulsive but you can't help wonder what makes them tick. Yet what's marvelous about "Appropriate Adult" (10 tonight, Sundance Channel) isn't that it lets you into the mind of a serial killer. Instead, what's revealed in the film is the perilous vulnerability of that attraction to them.

"Adult" is the true story of Brits Fred West (Dominic West) and his wife Rose (Monica Dolan) who murdered about a dozen women, including two of their children, over a decade. When the film opens, Fred West has been under suspicion for a while, so when the police bring him in this time, after his daughter disappears, they request an 'appropriate adult,' a person who sits in with vulnerable suspects during police interviews to look after their interest.