MPs on Tuesday night took the unprecedented step of debating the release from jail of Volkert van der Graaf, the animal rights activist who murdered politician Pim Fortuyn in 2003.

The debate came as the public prosecution department said it is carrying out a new psychiatric evaluation of Van der Graaf to assess if he is likely to reoffend.

Junior justice minister Fred Teeven said during the debate that he was not involved in that decision. ‘I did not give the public prosecution department the order to carry out new research,’ he said. ‘We were told in November they would do this.’

A legal expert told Nos radio on Wednesday the debate about Van der Graaf’s release is inappropriate given it is an issue for the courts, not politicians.

There has been disquiet in populist circles about Van der Graaf’s release, with supporters of Pim Fortuyn saying he should serve out his full 13-year sentence. Van der Graaf has served two-thirds of his sentence and is entitled to early release in May.