According to a report published on Wednesday by The Wall Street Journal quoting sources close to United States officials’ early assessment of evidence, the black box audio recording of the last conversation between the two pilots indicates that the captain might have turned off the switches controlling the flow of fuel to the plane’s engines.

A cockpit voice recording of doomed Air India Flight 171 indicates the younger co-pilot asked his more experienced colleague why he turned off the plane’s fuel-supply switches, according to people familiar with the matter.

The report and India’s inspection order referred to an advisory from the Federal Aviation Administration in 2018 that recommended that carriers using Boeing models, including the 787, inspect the locking mechanism of the fuel control switches to ensure they could not be moved accidentally.