Tatlock, according to the standard version of the story, suffered from intense depression and killed herself in January 1944. Her love of John Donne may have been why Oppenheimer named the first test for the atomic bomb “Trinity.” We don’t know; even Oppenheimer claimed not to know. It makes for a good story as it is, a poetic humanization of a weapons physicist and the first atomic test. Peer De Silva, the head of security for the Los Alamos laboratory, later wrote that he was the one who told Oppenheimer of Tatlock’s death, and that he wept: “[Oppenheimer] went on at considerable length about the depth of his emotion for Jean, saying there was really no one else to whom he could speak.”
But there may be more to the story. Gregg Herken’s Brotherhood of the Bomb (Henry Holt, 2002) was the first source I saw that really peeled apart the Oppenheimer-Tatlock story, and got into the details of the 1943 visit. Oppenheimer had told security he was visiting Berkeley to recruit an assistant, though Tatlock was always the real reason for the trip. He was being tailed by G-2 agents the entire time, working for Boris Pash, who was in charge of Army counterintelligence in the Bay Area. They tailed Oppenheimer and Tatlock to dinner (Mexican food), and then followed them back to Tatlock’s house. Army agents sat in a car across the street the entire night. The assistant that Oppenheimer hired was David Hawkins, who had his own Communist sympathies. The whole thing was a very dodgy affair (in many senses of the term) for the scientific head of the bomb project. Pash subsequently got permission to put an FBI bug on Tatlock’s phone.