While Boeing's push to lift the grounding of the 737 Max is making headlines, federal prosecutors have been quietly gathering information to determine if criminal conduct contributed to two deadly crashes of the troubled jetliner.
The prosecutors have been tight-lipped about the investigation, which only became known when they began issuing subpoenas. They have refused to even acknowledge the existence of the investigation, largely because of strict rules that prohibit them from discussing secret grand-jury proceedings.
But a window into their work emerged from a recent meeting in Washington, D.C., between prosecutors and a Kirkland-based consultant who has raised questions about Boeing's development of the plane.
While the consultant, Peter Lemme, was originally subpoenaed to appear before the grand jury, he instead underwent six hours of close questioning by two prosecutors in the U.S. Justice Department's Fraud Section, at least one federal agent and several other people.
"They're thorough," said Lemme, a former Boeing flight-controls engineer who is now an avionics and satellite-communications consultant.
The Department of Transportation's Inspector General and the FBI are participating in the probe, according to informed sources who have spoken on condition of anonymity because of the confidential nature of the inquiry.
Lemme agreed to describe the general parameters of his discussion, but said he'd abide by the prosecutors' request not to divulge specific questions that they said might taint or influence the testimony of other witnesses.
Although Lemme has no direct personal knowledge of the airplane's development or certification, he did a detailed analysis of the first crash, in which a Lion Air 737 Max 8 plunged into the Java Sea shortly after takeoff from Jakarta on Oct. 29, killing 189 people.
He was extensively cited as an expert in The Seattle Times in a March 17 story about the crashes, and subsequently in multiple other press accounts.
Lemme received a grand-jury subpoena on April 1, weeks after the second crash of an Ethiopian Airlines 737 Max 8 on March 10 near Addis Ababa. That crash, which killed 157 people, led to the international grounding of the Max fleet and Boeing's on-going efforts to gain approval of its fix to a new flight-control system on the plane.