Appointed head of the security police to capture Giuliano, Velardi worked alongside Luca Amato, discovering a secret network beneath Giuliano's home in Montelepre. Despite this, Velardi cooperated with Masino Croce, Stefano Andolini and Michael Corleone to have Giuliano escape to the United States, seeing it as preferable to having Giuliano rot in a prison cell or become a martyr in Palermo.
However, Velardi had no loyalty to the criminals who were effectively in charge of his office and later that year he captured Stefan Andolini in Palermo and interrogated to find information on Giuliano's location. When the criminal refused to talk, Velardi grew angry and they struggled, resulting in Andolini's death.
After the murder of Giuliano, Velardi feels free to arrest Michael Corleone and Peter Clemenza, who were in a cafe nearby. Don Croce tells Velardi to release them, but he refuses until he receives a call from his superior, the Italian Minister of Justice Franco Trezza ordering him to release them. He is shot to death in the streets a week later, likely on the orders of Don Croce.