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.

A cockpit recording suggests the captain may have shut off fuel switches before Air India Flight AI171 crashed, killing 260 people.

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.