A former Boeing employee who became a whistleblower against the company has been found dead amidst a lawsuit he had been aiding.

John Barnett died on March 9 at the age of 62 from what police have described as a “self-inflicted wound. Prior to his death, he had “been giving evidence in a whistleblower lawsuit against the company,” per the BBC. Barnett had retired from the company in 2017 for health reasons after working with Boeing for 32 years. The BBC writes:

From 2010, he worked as a quality manager at the North Charleston plant making the 787 Dreamliner, a state-of-the-art airliner used mainly on long-haul routes.

In 2019, Mr. Barnett told the BBC that under-pressure workers had been deliberately fitting sub-standard parts to aircraft on the production line.

He also said he had uncovered serious problems with oxygen systems, which could mean one in four breathing masks would not work in an emergency.

He said soon after starting work in South Carolina he had become concerned that the push to get new aircraft built meant the assembly process was rushed and safety was compromised, something the company denied.

He later told the BBC that workers had failed to follow procedures intended to track components through the factory, allowing defective components to go missing.

He said in some cases, sub-standard parts had even been removed from scrap bins and fitted to planes that were being built to prevent delays on the production line.

Barnett further said that emergency oxygen systems for the Boeing 787 had a failure rate of 25 percent in a real-life emergency, adding that he alerted upper management to the problems. While Boeing denied all of his claims, the Federal Aviation Administration (FAA) confirmed in 2017 that some of his arguments had merit, determining that the location of at least 53 “non-conforming” parts in the factory were considered lost, demanding that Boeing take “remedial action.”