The cause of the explosions which killed at least five people in The Hague and injured a further four early on Saturday morning is still unclear, but there are signs it could have been the result of criminal activity, justice minister David van Weel said on Sunday.

A major crimes team consisting of some 25 detectives has now been set up to look into the options, the AD reported.

Van Weel, who visited the scene with prime minister Dick Schoof on Sunday afternoon, said the police are investigating several scenarios “and that includes a crime”. He declined to give any further details.

The police are also still searching for a car that was spotted driving away from the explosion site on the Tarwekamp in the city’s Mariahoeve district just after the blasts. Police have also appealed for eyewitnesses to come forward and for any camera footage showing the car.

“If this turns out to have been a deliberate explosion, then that will be truly shocking,” the minister said. It would also further illustrate “the enormous problem” the Netherlands currently faces with firework bombs. “And if it is a crime, we will get them,” he said.

Police said last month over 1,000 firework bombs will have been set off outside Dutch homes and business premises by the end of this year.

The police had always worked on the assumption that most of the attacks could be linked to criminal gangs. However, research has since found that over half are the result of “domestic conflicts between non-criminal citizens, often over relationships”.

In total, 19 homes were damaged by the Saturday morning explosions and up to five were completely destroyed.

The police have not ruled out finding further bodies. “We cannot be 100% sure that everyone has been taken out of the rubble,” a spokesman for the regional security board said. “So we are still looking”.

A fund raising campaign for those affected by the blast had raised €250,000 by Sunday evening.