A former Boeing employee who had been giving evidence in a whistleblower lawsuit against the company has been found dead in South Carolina, authorities said.

The death of John Barnett, 62, was confirmed by the Charleston County Coroner. The office said in a news release that he died from “what appears to be a self-inflicted gunshot wound.” 

Barnett worked at Boeing for 32 years and retired in 2017, the BBC reported. From 2010 to 2017, he worked as a quality manager at the airplane manufacturer’s North Charleston plant. The plant manufactured the 787 Dreamliner, which was the subject of multiple whistleblower complaints. 

Barnett told the BBC in 2019 that he had uncovered serious problems with oxygen systems on the long-haul jet. Boeing said that it had “identified some oxygen bottles received from the supplier that were not deploying properly,” the BBC said, but said that none of those defective bottles were ever installed. 

Barnett also alleged that sub-standard parts that were set to be discarded were fitted to planes to avoid production delays, the BBC reported, and said that he believed the push to build new aircraft meant a rushed process that compromised passengers’ safety. Barnett told the BBC that he had alerted managers to his concerns, but no action was taken. A panel of experts recently criticized Boeing’s safety culture, telling the Federal Aviation Administration that there was a “disconnect” between Boeing’s senior management and workers, and concerns of retaliation. 

Boeing has denied Barnett’s allegations, the BBC reported. A 2017 review by the Federal Aviation Administration did find that the location of at least 53 “non-conforming” parts in the North Charleston factory were unknown, mirroring one of Barnett’s allegations, and ordered the airline to take remedial action. 

Barnett had accused Boeing of denigrating his character and hampering his career. The manufacturer has denied these allegations.

Barnett was was in Charleston this week to give a formal deposition in relation to a defamation lawsuit he had filed against Boeing, the BBC reported. He was expected to appear for further questioning on Saturday, but failed to appear. He was found dead in his truck in the hotel’s parking lot, the BBC said. 

Boeing said in a statement to CBS News that they were “saddened by Mr. Barnett’s passing,” and said their “thoughts are with his family and friends.” 

CBS News has reached out to Barnett’s lawyer, but did not get an immediate response. 

Boeing has drawn scrutiny for a series of recent incidents. On Monday, at least 50 people were injured by what officials described as a “strong movement” on a Boeing 787-9 Dreamliner traveling from Sydney to Auckland, New Zealand.

In January, a door plug flew off an Alaska Airlines Boeing 737 Max shortly after the plane took off from Portland, Oregon, forcing an emergency landing. A preliminary report from the National Transportation Safety Board suggested that four key bolts were not fitted. The incident is under investigation from the Federal Aviation Administration and the Justice Department. 

Earlier this month, a United Airlines flight traveling from San Francisco to Japan had to make an emergency landing at Los Angeles International Airport after the Boeing 777 plane lost a tire shortly after takeoff. Meanwhile, an unspecified “maintenance issue” forced another United Airlines flight traveling from Australia to San Francisco to return to Sydney Kingsford Smith Airport on Monday. That plane was a Boeing 777-300.