Jiang Hui's mother had been on holiday with a friend in Malaysia and boarded a plane to fly home to Beijing on March 8, 2014. But she never arrived. What happened to her flight, MH370, is one of the biggest mysteries in aviation history. No one knows what happened on board: Was there a hijacking, an accident or did a crew member commit suicide? The wreckage of the plane has never been found either. The search has now been called off, but Jiang Hu refuses to accept that. He wants to know what happened to his mother. He and his fellow campaigners accuse the Malaysian authorities of a lack of transparency and tact. Jiang Hui says he can live with whatever scenario brought the plane down; he just wants to know what really happened. A report by Mathias Bölinger.