The Iceman (2012) is a fictionalized version of this real life story. Michael Shannon was able to emulate the real Richard Kuklinski's voice by listening to this documentary and TV Interviews.
The film is called The Iceman Tapes: Conversations with a Killer (1992) because Richard Kuklinski's modus operandi in his contract killings was to freeze the bodies of his victims to obscure their time of death.