Ronnie, the US doesn't usually execute spies outside of wartime. One could easily point to the example of the CIA employee Aldrich Ames, who was turned and used as a Soviet spy, and directly accountable for up to a dozen deaths of American agents and their contacts in the Soviet Union. He, is still alive and kicking.
U.S. confirms ISIS computer expert killed in air strike (Reuters)
from the article: Think before you sing `Hatikva'