\" \" Wayne Williams, then a suspect in the Atlanta Child Murders, is led away in handcuffs. Many believe Williams killed some, but not all, of the victims. These common threads pointed to a single serial killer. But their actions raise a question mark as to whether there were additional murderers and not one serial killer. NOW THAT'S INTERESTING The world's most prolific serial killer is believed to be Pedro Alonzo Lopez, who killed more than 300 girls and women.