CHARLESTON, South Carolina (KAKE) - A former Boeing quality manager was found dead of a self-inflicted wound last weekend.

John Barnett, who worked for Boeing's North Charleston, South Carolina plant for 32 years until he retired in 2017, was found dead on March 9, according to ABC affiliate WCIV-TV. The Charleston County Coroner's office said Barnett died from a self-inflicted gunshot wound, and an investigation is ongoing.

Leading up to his death, the 62-year-old had been giving evidence in a whistleblower lawsuit against the company, and was in Charleston for legal interviews for the lawsuit. 

In 2010, Barnett worked as a quality manager at the plant that was making the 787 Dreamliner. In a 2019 interview with the BBC, Barnett said that he became concerned that the push to get the new aircraft built meant the assembly process was rushed and safety was compromised. He alleged that under-pressure workers had been deliberately fitting sub-standard parts to aircraft on the production line, and parts had been removed scrap bins and fitted to planes to prevent delays. In addition, he had uncovered serious problems with oxygen systems, meaning that one in four breathing masks would not work in an emergency.

Barnett alerted managers of his concerns, but no action was taken. The company denied his assertions, but a 2017 FAA review did uphold some of his concerns.

In a statement sent to the BBC, Boeing said, "we are saddened by Mr. Barnett's passing, and our thoughts are with his family and friends."

Barnett's death comes at a time where Boeing and key supplier Spirit AeroSystems have been under intense scrutiny. In January, a door plug blew off of a 737 Max shortly after take-off from Portland International Airport. A preliminary report from the US National Transportation Safety Board suggested that four key bolts were not properly fitted to hold the plug in place.

Last week, the FAA said a six-week audit of the company had found "multiple instances where the company allegedly failed to comply with manufacturing quality control requirements".