Three of the men involved in the December explosion at an apartment complex in The Hague, which left three people dead, are now officially suspected of murder, the public prosecution department said on Wednesday.

The first pro-forma court hearing takes place on March 14, and the department has expanded the charge sheet in the run-up to that date. Initially, the four suspects faced charges related to the explosion.

They now face charges of murder, attempted murder, causing a fatal explosion, and arson, the department said in a statement.

The four suspects range in age from 23 to 33 and come from Rotterdam, Roosendaal, and Oosterhout. The suspect from Oosterhout does not face murder charges.

The police investigation has shown that approximately 200 litres of petrol were used in the blast at a bridal shop on the Tarwekamp and was likely thrown over clothing on display.

The explosion and fire caused the partial collapse of the building, killing three members of one family and three others. Four other people were taken to hospital.

One of the suspects is the ex-partner of the bridal shop owner.