Tony got the idea for his shotgun contraption from television show Hawaii Five-O, season 3 episode 14, "The Double Wall".
Tony Kiritsis had done a similar crime to his sister six years earlier. A the end of a gun Tony held his sister hostage until his family came up with $50k. The family gave him the money and refused to prosecute him. Ironically he took the $50k and used it as a down payment for the property he tried to save by taking Dick Hall hostage.
Some of the footage used in this film has been previously seen in the 1981 'Shock-umentary' 'The Killing Of America' that used other scenes of violence & gun crime including the deaths of John & Bobby Kennedy as a critique of U S culture