On 6 January 2003, Van der Graaf was moved to the Pieter Baan Centrum (PBC) to begin the seven-week behavioural investigation. Disagreements between the Ministry of Justice and the management of the PBC over the conditions of his supervision delayed it. The Ministry wanted Van der Graaf under video surveillance 24 hours per day and isolated from other patients for his own safety. The PBC believed such cameras would prevent establishing the trust needed for the multi-disciplinary behavioural investigation. It took responsibility to supervise him in a small group so that the investigation could proceed optimally. On 20 January, Van der Graaf said he was suspending his cooperation for the investigation. The Minister of Justice, Piet Hein Donner, resolved the dispute by dropping the demands for video surveillance and isolation.