The United States Department of Justice (DOJ) is opening a criminal investigation into Boeing over a blown-out door plug aboard an Alaska Airlines flight in January. 

According to the Wall Street Journal, DOJ investigators have begun reaching out to passengers and crew who were on the flight. 

The door plug on the 737 MAX line operated by Alaska blew out minutes after it took off from Portland International Airport on January 5. Although no injuries were reported, the incident has led to a slew of controversy for Boeing, as the company has faced increased scrutiny over its manufacturing processes.

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The DOJ’s criminal investigation will look into whether Boeing was in compliance with a settlement over a pair of deadly crashes in 2018 and 2019 respectively. According to Associated Press, Boeing has acknowledged in a letter to Congress that it cannot find records for work done on the door panel of the Alaska Airlines plane.

“We have looked extensively and have not found any such documentation,” Ziad Ojakli, Boeing executive vice president and chief government lobbyist, wrote to Senator Maria Cantwell on March 8.

Neither the DOJ nor Boeing have commented on reports of this new investigation. In a statement provided to the Associated Press, Alaska Airlines said that “in an event like this, it’s normal for the DOJ to be conducting an investigation.” 

“We are fully cooperating and do not believe we are a target of the investigation,” they added.