The FBI has launched a nationwide investigation into the deaths or disappearances of at least 10 scientists and research staff linked to sensitive U.S. projects, including several from the Los Angeles area.

Officials said they are working with multiple federal and local agencies, and Congress has also opened a separate inquiry over potential national security risks.

The cases span several years and include a mix of confirmed deaths, unsolved disappearances, and one murder for which an arrest has been made.

Authorities stressed that there is currently no confirmed evidence connecting the incidents or indicating a coordinated threat, the Los Angeles Times has reported.

NASA and other institutions involved say they are cooperating and have not identified any national security link so far.