WASHINGTON — U.S. prosecutors are looking into the development of Boeing’s 737 Max jets, a person briefed on the matter revealed Monday, the same day French aviation investigators concluded there were “clear similarities” in the crash of an Ethiopian Airlines Max 8 last week and a Lion Air jet in October.

The Justice Department probe will examine the way Boeing was regulated by the Federal Aviation Administration, said the person, who asked not to be identified because the inquiry is not public.

A federal grand jury in Washington sent a subpoena to someone involved in the plane’s development seeking emails, messages and other communications, the person told The Associated Press.

The Transportation Department’s inspector general is also looking into the FAA’s approval of the Boeing 737 Max, a U.S. official told AP. The official wasn’t authorized to discuss the matter publicly and spoke on condition of anonymity. The Wall Street Journal reported on the probe Sunday said the inspector general was looking into the plane’s anti-stall system. It quotes unidentified people familiar with both cases.

The anti-stall system may have been involved in the Oct. 29 crash of a Lion Air jet off of Indonesia that killed 189 people. It’s also under scrutiny in the March 10 crash of an Ethiopian Airlines jet that killed 157.

The Transportation Department’s FAA regulates Chicago-based Boeing and is responsible for certifying that planes can fly safely.

The grand jury issued its subpoena on March 11, one day after the Ethopian Airlines crash, according to the person who spoke to The Associated Press.

Spokesmen for the Justice Department and the inspector general said Monday they could neither confirm nor deny the existence of any inquiries. The FAA would not comment.

“Boeing does not respond to or comment on questions concerning legal matters, whether internal, litigation, or governmental inquiries,” Boeing spokesman Charles Bickers said in an email.