While he was opposition leader, Abhisit Vejjajiva accused Thaksin of crimes against humanity for his alleged role in the campaign. After being appointed Prime Minister, Abhisit opened an investigation into the killings, claiming that a successful probe could lead to prosecution by the International Criminal Court. Former attorney-general Kampee Kaewcharoen led the investigation and the investigation committee was approved by Abhisit's Cabinet. Abhisit denied that the probe was politically motivated. Witnesses and victims were urged to report to the Department of Special Investigation, which operated directly under Abhisit's control.