A former Boeing manager who raised safety questions about the aircraft maker has been found dead outside a hotel in South Carolina, according to local authorities.

The body of John Barnett, 62, was found Saturday in a car outside a Holiday Inn, suffering from what the Charleston County Coroner's Office said appeared to be a self-inflicted gunshot wound. The Louisiana resident was pronounced dead at the scene.

Police in Charleston said detectives were waiting for a formal determination of the cause of death and "any additional findings that might shed further light on the circumstances surrounding" the end of Barnett's life. Police noted "the global attention this case has garnered."

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.

"John was deeply concerned about the safety of the aircraft and flying public, and had identified some serious defects that he felt were not adequately addressed," Barnett's brother, Rodney, said in a family statement to The Associated Press on Tuesday. "He said that Boeing had a culture of concealment and was putting profits over safety."

Rodney Barnett said working at Boeing created stress for John.

"He was suffering from PTSD and anxiety attacks as a result of being subjected to the hostile work environment at Boeing, which we believe led to his death," the brother said.

Boeing, in a one-sentence statement, said, "We are saddened by Mr. Barnett's passing, and our thoughts are with his family and friends."

Experts say the reasons people take their own lives are complicated, and that recent increases in suicides could be driven by several factors, including higher rates of depression and limited access to mental-health services.

In 2019, Barnett told The New York Times about quality issues at Boeing's factory in South Carolina, where the 787 jetliner is assembled.

Barnett said he found discarded metal shavings near wiring for the flight controls. He said it could have been "catastrophic" if the sharp pieces had pierced the wiring. He said after he complained to superiors, they moved him to another part of the plant.

Barnett told the BBC that same year that up to a quarter of the oxygen systems on the 787 - a two-aisle plane that airlines use mostly for international flights - might not work because of faulty parts installed at the Boeing plant. Boeing denied the claim.

Barnett filed a whistleblower complaint with the government, which is still pending. A hearing on the case was scheduled for June.

Boeing's production practices have been questioned both on the 787, a model called the Dreamliner, and the company's best-selling plane, the 737 Max. The company has come under increased scrutiny since a panel blew off a 737 Max during an Alaska Airlines flight in January.

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EDITOR'S NOTE -- This story includes discussion of suicide. The national suicide and crisis lifeline is available by calling or texting 988. There is also an online chat at 988lifeline.org.

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James Pollard in Columbia, South Carolina, contributed to this report.