Dutch police are liable for a mass shooting because the gunman should never have been granted a firearms licence, a court has ruled.

Tristan van der Vlis killed six people and injured 16 others when he unleashed a hail of automatic gunfire in a packed shopping mall in April 2011.

The 24-year-old later died after turning the gun on himself. In a letter to his parents before the attack, Van der Vlis said he was unhappy and wanted to kill himself.

The Netherlands was left in mourning after the attack in Alphen aan de Rijn - with one witness describing it as the day the country "lost its innocence".

An appeals court has now concluded that the police were negligent in granting Van der Vlis a licence to own guns, as a previous application by the attacker was rejected because he had illegally fired an airgun.


Van der Vlis also suffered from psychological problems dating back to 2006, which should have raised a red flag with the police.

The appeal court's judgment quashes a 2015 ruling by a lower court which concluded that the police had merely made mistakes in the case.

As a result, the judges have ordered the police to pay compensation to the families of those killed and wounded - in addition to the court costs of 51 plaintiffs.

The surprise ruling comes as the issue of gun control is high on the global agenda following a series of deadly shootings in the US.