Dennis Andrew Nilsen was a thirty-seven-year-old government worker whom London police arrested after the discovery that the sewer below his home was blocked by human body parts. Nilsen readily admitted to strangling fifteen young men over the previous four years, then dismembering and disposing of the bodies in various ways.

Born in 1945 in a Scottish fishing village on the North Sea, Nilsen grew up in an impoverished home with two siblings and four half-siblings from his mother's second marriage. In 1961, at the age of fifteen, he enlisted in the British Army and spent the next eleven years as a cook. Moving to London in 1973, Nilsen eventually found a job as a civil servant at a government employment office but remained alienated and friendless. His only companion was a mongrel named Bleep, to whom he seemed devoted, as neighbors later reported.

Nilsen had a series of unsuccessful relationships with...