In a deleted scene, CIA informant Pam Bouvier mentions that Heller is an "ex-Green Beret colonel", a former member of the United States Army Special Forces. Like Truman-Lodge, he is wanted in the United States.
Heller is an ex-green beret colonel of the US Army turned head of Sanchez's military and security. Heller is a trusted henchman until one night, Pam Bouvier of CIA came into Sanchez' casino with the then rogue agent James Bond and when Bond left to get to a vantage point to shoot Sanchez, Pam went up Heller and showed him a letter and then when 007 blew up the window to Sanchez' office, Heller got scared and went to Sanchez as Bond was about to fire but was stopped by Kwang's Narcotic ninjas. Heller soon joined Sanchez during the raid on their base and killed all the Narcotic agents including an MI6 agent sent by M to bring Bond back to London.
When Bond recovered at Sanchez' home and escaped with Lupe Lamora's help, 007 learnt from Pam that Felix Leiter gave Pam the letter which is revealed to be a letter of immunity if Heller took some Stinger missiles, but when Bond missed the shot, Heller got scared and said the deal was off.
Heller assists later in the death of Milton Krest by Sanchez.
Later on, when Bond set fire to Sanchez' drug factory, Heller attempted to get the Stingers away from the chopper but was caught by Sanchez's henchman Braun and upon lying, saying "Making sure these were secure" Braun had Heller stabbed on a forklift's pallet holder and had the body and forklift ram into a wall, undoubtedly helped Bond and Pam escape the burning building.