 Patrick Kilpatricks part is based on The Iceman, Richard Kuklinksi,  a sociopathic serial killer, who made a living killing people for  the Gambino crime family, when he wasnt killing people because they  ticked him off. Kuklinski was partly made the way he was, because of  the extremely violent and terrifying upbringing he received. When he  wasnt killing people, he maintained a seemingly ordinary home, with  a wife three children, who believed he was a successful businessman.