The parents of a man who killed five people in a shopping mall have been ordered to give evidence in a court case to decide if they should be held liable for their son’s mental condition.

Victims of the shooting in Alphen aan den Rijn six years ago claim Tristan van der Vlis’s parents were aware their son was having serious difficulties but failed to act. ‘They did not do enough to prevent the incident,’ lawyer Lionel Lalji told the district court in The Hague.

The 24-year-old opened fire in the Ridderhof shopping centre in April 2011. In addition to the fatalities, 17 people were wounded before he turned the gun on himself.

The victims represented by Lalji want his parents to be held responsible so that they can claim compensation from their insurers. They argue that Van der Vlis’s father should have reported that he had a son living at home with a serious disorder when he applied for a firearms licence in 2007. This would have made it harder for his son to acquire a weapons licence the following year.

The court said it wanted to ask his parents questions about his psychological condition on the day of the shooting, as well as details of their insurance policy, in a later hearing.

Other families have distanced themselves from the claim. Lawyer Orlando Kadir, who is representing a different group of victims in a civil suit against the police, said Lalji’s case had ‘no chance’.

Kadir’s claim was dismissed by the court in The Hague two years ago, although the judges said mistakes had been made in the processing of Van der Vlis’s firearms licence in 2008. The decision has been appealed.