John Barnett, 62, of Louisiana, was found dead March 9, and police had said earlier that his injuries were self-inflicted.
Barnett was a longtime Boeing employee and worked as a quality-control manager before he retired in 2017. In the years after that, he shared his concerns with journalists.
Barnett said he saw discarded metal shavings near wiring for the flight controls that could have cut the wiring and caused a catastrophe. He also noted problems with up to a quarter of the oxygen systems on Boeing’s 787 planes.