Paz is the tertiary antagonist in the film The Bourne Ultimatum. He is an asset of Operation Blackbriar sent to kill journalist Simon Ross.
When Noah Vosen discovers a journalist named Simon Ross has information about Blackbriar, and after he finds out Bourne is helping Simon, Noah orders the nearest asset to be activated. While Paz is resting in a hotel room he receives the orders to pursue and terminate both Jason Bourne and Simon. While other CIA agents are not able to capture Bourne and Simon, Paz easily spots them and gets ready to fire. Under orders from Noah Vosen Paz assassinates Simon at Waterloo Station.
In New York, Paz pursues Jason Bourne following the latter's infiltration of Vosen's office. In the ensuing car chase, Paz is injured and vulnerable but Bourne spares him.
Later Paz confronts Bourne on the roof of the Treadstone training facility. The situation switched, Paz holds Bourne at gunpoint and demands to know why he was spared. Bourne asks, "Do you even know why you're supposed to kill me?" Then Bourne repeats the dying words of the Professor, "Look at us. Look at what they make you give." When Bourne turns and runs for the ledge, Paz lowers his gun and fails to fire.