9Dennis NilsenDennis Nilsen, also known as the "Muswell Hill Murderer" and the "Kindly Killer" is a British serial killer and necrophiliac who lived in London. Nilsen is known to have gruesomely murdered at least 15 men and boys between 1978 and 1983, and attempted to murder several others. After he killed his victims he would retain their corpses for company and sex acts. He was apprehended when a plumber found the cause of his blocked drains were dismembered human entrails.