Police said the gunman Ali Sonboly began planning the shooting attack a year ago after visiting the German city of Winnenden where another teenage killed 15 people in 2009.

警方称凶犯阿里桑波里一年前就已预谋，他曾前往温嫩登市，2009年另一名青年在温嫩登制造枪案，造成15人遇难。