The most prolific serial killer was born in the UK. He was a General Practitioner Dr, usually described as kind, friendly, thoughtful but also a pathological liar - "he was a nice guy". His patients were mainly elderly women, who adored his family Dr. He was not remmarkable, he just fitted in to our society in a way that helped him to murder for over 23 years. sources: Wikipedia, magazine crime monthly, serial killers and Welldoing website.