NEW DELHI -A preliminary investigation into the crash of an Air India passenger jet last month that killed 260 people raises additional questions about the incident and the investigation is far from over, Air India's CEO said in a memo on Monday.

CEO Campbell Wilson said in an internal memo that the airline is open to further inquiries and warned against "premature conclusions."

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