Joe Natuman and the former police commissioner, Aru Maralau, are on trial in the Supreme Court, accused of trying to pervert the course of justice.
Mr Natuman is accused of trying to stop a police team from investigating high-ranking officers, including Mr Maralau, when he was prime minister in 2014.
But their lawyer, Nigel Morrison, sought to have the case dismissed, arguing that the prosecution did not establish that there was any criminal intent to interfere.