Thirteen of the 31 people injured in Sunday’s monster truck stunt show in Haaksbergen remain in hospital, doctors said on Tuesday evening.

Two adults and a five-year-old boy were killed when a truck careered into the crowd watching the show. Several of those in hospital have very serious injuries.

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.

The driver of the truck has been arrested. Mario D says in an open letter in Wednesday’s Telegraaf he is devastated by the accident. ‘No-one wanted this to happen,’ he told the paper. He did not go into the likely cause.