"The events you are about to see may have been buried or covered up. Those with traceable records have been marked with the specific date they occurred on. Verify at your own risk, but trust no one."
SPOILERS AHEAD FOR PHANTOM DOCTRINE’S CAMPAIGN!
After recovering documents, Deadpan learns of an operation codenamed “Walter Poon.” After contacting Leslie, he learns that Walter Poon was Leslie’s undercover name back in Hong Kong. Leslie tells Deadpan to visit the U.S. Embassy in Beirut, saying he has “killer stuff” to show. Later, after traveling to Beirut, Deadpan learns suicide bombers attacked the U.S. Embassy there, killing Leslie along with a few civilians. It is revealed that this was the objective of Operation Walter Poon: to kill Leslie.