Scorsese and Pileggi collaborated on the script for five months, towards the end of 1994. Real-life characters were reshaped, such as Frank "Lefty" Rosenthal, Geri McGee, Anthony Spilotro, and Spilotro's brother Michael. Some characters were combined, and parts of the story were set in Kansas City instead of Chicago. A problem emerged when they were forced to refer to Chicago as "back home" and use the words "adapted from a true story" instead of "based on a true story." Real life mobster turned witness Frank Cullotta inspired the character Frank Marino (played by Frank Vincent), served as a technical advisor for the film, and also played an on-screen role as a hitman.