Called "the Monster of the Andes," Pedro Lopez is believed to have murdered as many as 300 young girls in South America. Born in 1949, Lopez was one of 13 children born to a prostitute mother. At the age of eight, he molested his sister, and his mother ejected him from the household. While jailed for auto theft as a teen, he killed three men who sexually assaulted him and craved to commit the act once again when he was released.

Lopez began frequenting crowded market squares looking for little girls, whom he then lured away to rape and strangle. The murders usually took place at an isolated spot, and he buried his victims' bodies. At one point in the late 1970s, a community of Peru's Ayacucho Indians caught him trying to abduct a nine-year-old. They planned to administer justice according to their own customs, which would involve ritual beating, torturing, then burying him alive. A missionary convinced them, however, to let the authorities handle it, which they did by deporting Lopez to Ecuador, where he continued to kill. As he later admitted, in 1980, Lopez was killing three young girls a week. That same year, he was caught trying to lure a twelve-year-old and was jailed. A flash flood caused the body of one of his victims to be discovered, and Lopez then confessed to dozens of slayings. He showed police more than 50 graves. He was jailed in Ecuador until 1998, when authorities deported him to Colombia, where he faced additional murder charges.