> More recently, and more sensationally, there is an entire chapter on Tatlock’s death in Kai Bird and Martin Sherwin’s biography of Oppenheimer

I read American Prometheus last summer, and did not walk away with any inkling that the discussion of Tatlock's death was sensational at all. I just re-skimmed that chapter and while it documents the questions others brought up later, the authors do not seem to imply they thought it was more than a suicide. They conclude by saying Oppenheimer never thought it more than suicide.