Flight data from a black box recovered from the China Eastern Airlines (600115.SS) jet that crashed in March indicates someone in the cockpit intentionally crashed the plane, the Wall Street Journal reported on Tuesday, citing people familiar with U.S. officials’ preliminary assessment.

A Western official told Reuters that the focus is on the actions of the crew after the preliminary investigation did not find any indication of a technical malfunction.

Boeing Co (BA.N), the maker of the jet, and U.S. National Transportation Safety Board (NTSB) declined to comment and referred questions to Chinese regulators.

In March, the Boeing 737-800 jet, which was en route from Kunming to Guangzhou, crashed in the mountains of Guangxi, after a sudden plunge from cruising altitude, killing all 123 passengers and nine crew members aboard. It was mainland China’s deadliest aviation disaster in 28 years. read more

The pilots did not respond to repeated calls from air traffic controllers and nearby planes during the rapid descent, authorities said.

China Eastern could not immediately be reached for comment Tuesday but the Wall Street Journal said the airline had said in a statement that no evidence emerged that could determine whether or not there were any problems with the accident aircraft.

The Chinese Embassy in Washington did not immediately respond to a request for comment.

In mid-April, China Eastern resumed use of the 737-800 planes. In a summary of its preliminary crash report last month, Chinese regulators did not point to any technical recommendations on the 737-800, which has been in service since 1997 with a strong safety record, according to experts.

NTSB Chair Jennifer Homendy said in a May 10 Reuters interview that board investigators and Boeing had traveled to China to assist the Chinese investigation. She noted that the investigation to date had not found any safety issues that would require any urgent actions.

Homendy said if the board has any safety concerns it will “issue urgent safety recommendations.” The NTSB also assisted Chinese investigators with the review of the flight data recorder and cockpit voice recorder at its U.S. lab in Washington.

Shares of Boeing were up 6.1% in afternoon trade.