Peter R. de Vries, who is a crime reporter, mentioned a 9mm. But it seemed to be a special cartridge instead of the 9x19 mm (Parabellum). The rounds were longer than normal ones, 23 or 25 mm in length. And that this ammo was not used in the criminal circuit, so he got it from some one special. He didn't have a permit, by the way. So the gun was illegal.
But as far as I know police didn't confirm this, except for the illegal gun.