A Cuban by birth, Santiago was selected by Carlo Tramonti and trained as a marksman in order to shoot President Shea. He was a light-skinned man who spoke perfect English and carried a Florida license that indentified him as Belford Williams. On the day of the shooting, he was hiding in the crowd at the Fontaineblue Hotel in Miami where Shea was showing himself to the public and the press. When Shea headed towards the crowd under heavy protection, Santiago managed to shoot him in the chest and neck with a 9mm beretta. Santiago was killed by two Secret Service agents immediately afterwards.