Illustration: Sarah Grillo/Axios. Stock: Getty Images The disappearances and deaths of at least 10 scientists, researchers and staffers who worked on nuclear and space programs are raising alarms on Capitol Hill. The big picture: The cases date back to at least 2023, but national security concerns prompted a House Oversight Committee investigation. Chairman James Comer (R-Ky.) and Rep. Eric Burlison (R-Mo.) sent letters to FBI Director Kash Patel, NASA administrator Jared Isaacman, Energy Secretary Chris Wright and Defense Secretary Pete Hegseth, seeking information on the deaths and disappearances, and "the processes and procedures in place to protect American scientific secrets and ensure personnel safety." What prompted the probe? The committee's letter did not cite a specific reason for the investigation, but referenced "unconfirmed public reporting" on the cases, including the recent disappearance of retired Air Force Maj. Gen. William Neil McCasland .…