Four people who were injured when a monster truck ploughed into the crowd at a show in the small town of Haaksbergen remain in hospital, over three weeks after the incident.

Two adults and a five-year-old boy were killed when a truck careered into the crowd watching the show. In total 31 people were injured and 13 spent several days in hospital.

The Dutch safety research council has launched an investigation into the accident. The show took place in a relatively small space and spectators were closer to the trucks than recommended in international truck show regulations.