John Barnett had worked for Boeing for 32 years, until his retirement in 2017.
In the days before his death, he had been giving evidence in a whistleblower lawsuit against the company.
Boeing said it was saddened to hear of Mr Barnett’s passing. The Charleston County coroner confirmed his death to the BBC on Monday.
It said the 62-year-old had died from a “self-inflicted” wound on 9 March and police were investigating.
That’s the most annoying misunderstanding. A conspiracy is still a conspiracy when you prove it happened/it’s happening. Conspirators remain conspirators, which means they were working together to do something illegal in secret. Ok, so now it’s not secret anymore, but they still conspired.