One month after an Air India flight crashed and killed over 200 people, investigators on Saturday revealed the fuel to both engines of the Boeing 787 plane had been mysteriously cut off prior to the incident.

Preliminary findings into last month’s Air India plane crash suggest the aircraft’s fuel control switches were turned off, causing a loss of engine thrust shortly after takeoff.

An official report on the world’s deadliest aviation accident in a decade, seen by CNN, has answered one key question – but raised others.