An American Airlines Boeing 737 MAX 8 flight from Los Angeles lands at Reagan National Airport shortly after an announcement was made by the FAA that the planes were being grounded by the United States in Washington, March 13, 2019.

U.S. prosecutors are looking at whether Boeing provided incomplete or misleading information about the 737 Max aircraft to U.S. air-safety regulators and customers, according to a report by the Wall Street Journal.

The aircraft is the same model involved in two fatal crashes in less than five months. The Ethiopian Airlines jet that crashed on March 10, killing all 157 aboard, and the Lion Air plane that went down in Indonesia on Oct. 29, which killed all 189 passengers and crew, were both 737 Max jets.

Although Boeing hasn't been accused of any wrongdoing, people close to the matter said the focus on disclosures to regulators is part of a broader investigation into how the jetliner was developed and certified, said the Journal.

Earlier this week it was reported that the original safety analysis that Boeing delivered to the FAA for a new flight control system on the Max, called the Maneuvering Characteristics Augmentation System, or MCAS, had several major flaws. This report is the one used to certify the plane as safe to fly.

"The 737 Max was certified in accordance with the identical FAA requirements and processes that have governed certification of all previous new airplanes and derivatives," Boeing told the Journal.

People close to the matter said agents with the Federal Bureau of Investigation and the Transportation Department's inspector general's office are working together under the direction of federal prosecutors, reported the Journal.

Read more about the investigation in the Wall Street Journal report.