A dead drop or dead letter box is a method of espionage tradecraft used to pass items or information between two individuals (e.g., a case officer and an agent, or two agents) using a secret location. By avoiding direct meetings, individuals can maintain operational security. This method stands in contrast to the live drop, so-called because two persons meet to exchange items or information.
This episode takes place Sunday April 12, 1981. At the beginning of the episode the radio baseball play-by-play mentions Leonard pitching and that the O's won the opener of the series on Friday, 5-3. This would be Dennis Leonard of the Kansas City Royals, who pitched on Sunday at Baltimore, with the Orioles losing the game, 4-2. The Orioles won the opener of that series on Friday, April 10, 1981, by a score 5-3.