Serial Killers - The nature versus nurture debate

In episode 1, author Janine Lazarus, Dr Gerard Labuschagne - former head of the police’s psychiatric unit and Jacaranda FM news editor Marius van der Walt discuss and explore the characteristics of serial killers that cut across almost all of them.
They are very often family men with sinister secrets. They take care of abused animals; can be a community’s much-loved babysitter; open support groups for drug addiction, etc. Are people born serial killers, or is it their upbringing that makes them into what they become?