A former Boeing employee who blew the whistle on alleged safety problems at the aircraft manufacturing giant has been found dead.

John Barnett, 62, died on Saturday from an apparent “self-inflicted” wound, a coroner in South Carolina in the United States said on Monday.

“Charleston City Police Department is the investigating agency. No further details are available at this time,” the office of Charleston County Coroner Bobbi Jo O’Neal told Al Jazeera in a statement.

Boeing, where Barnett worked for more than three decades until his retirement in 2017, expressed condolences at the news of his death.

“We are saddened by Mr. Barnett’s passing, and our thoughts are with his family and friends,” the Seattle-based aircraft manufacturer told Al Jazeera in a statement.

Brian Knowles, a lawyer in South Carolina who represented Barnett, did not immediately respond to a request for comment.

The BBC, which first reported the news of Barnett’s death, said the former employee had been giving evidence in a whistleblower lawsuit against the company in recent days.

In 2019, Barnett was quoted by the BBC alleging that Boeing had deliberately fitted planes with faulty parts and that passengers on its 787 Dreamliner could be left without oxygen in the event of a sudden decompression.

In 2014, an Al Jazeera investigation released after the Dreamliner was briefly grounded following two battery failures revealed that workers at Boeing’s Charleston plant had serious concerns about the aircraft’s safety.

Boeing, which dominates the market for commercial aircraft along with Netherlands-based Airbus, has been under intense scrutiny over its safety record since two fatal crashes involving the Boeing 737 MAX in 2018 and 2019.

On Monday, dozens of people suffered injuries, most of them minor, when their Boeing aircraft en route to New Zealand from Australia experienced what airline officials described as a “strong movement” caused by a “technical event”.

The incident was the latest in a series of safety-related events since the beginning of March, including an engine fire that forced a Boeing 737 to make an emergency landing in Houston, Texas shortly after takeoff.

On Saturday, US media outlets reported that prosecutors had opened a criminal investigation into January’s mid-flight blowout of a Boeing 737 MAX operated by Alaska Airlines.

A preliminary report by the US National Transportation Safety Board into the incident found evidence suggesting that four key bolts designed to hold the door in place had been missing.

The US Federal Aviation Administration (FAA) said last week it had given Boeing 90 days to come up with a plan to correct problems in its production and shortage procedures following an audit that identified “non-compliance issues”.

A separate FAA report released last month found serious problems with Boeing’s safety culture, including fears of retaliation among employees with safety concerns.