David Wise in Smithsonian Magazine:
They had flown in two days earlier for this mission: to break into the embassy of a South Asian country, steal that country’s secret codes and get out without leaving a trace. During months of planning, they had been assured by the local CIA station that the building would be empty at this hour except for one person—a member of the embassy’s diplomatic staff working secretly for the agency.
But suddenly the driver’s hand-held radio crackled with a voice-encrypted warning: “Maintain position. Do not approach target.” It was the local CIA station, relaying a warning from the agency’s spy inside: a cleaning lady had arrived.
From the back seat Douglas Groat swore under his breath. A tall, muscular man of 43, he was the leader of the break-in team, at this point—1990—a seven-year veteran of this risky work. “We were white faces in a car in daytime,” Groat recalls, too noticeable for comfort. Still they waited, for an hour, he says, before the radio crackled again: “OK to proceed to target.” The cleaning lady had left.
Groat and the others were out of the car within seconds. The embassy staffer let them in the back door. Groat picked the lock on the code room—a small, windowless space secured for secret communications, a standard feature of most embassies—and the team swept inside. Groat opened the safe within 15 minutes, having practiced on a similar model back in the States. The woman and two other officers were trained in photography and what the CIA calls “flaps and seals”; they carefully opened and photographed the code books and one-time pads, or booklets of random numbers used to create almost unbreakable codes, and then resealed each document and replaced it in the safe exactly as it had been before. Two hours after entering the embassy, they were gone.
More here.