There's a movie about that which focuses on Berg who was a pretty impressive person. He was a MLB player at a time when that was the biggest sport in the US but the players made next to nothing. He also spoke 10 languages fluently and spent most of the war translating intelligence intercepts. Supposedly he found Heisenberg but judged that he wasn't a threat and so didn't kill him. That's the story anyway, no idea how true that is.