A Papua New Guinea policeman is suspected to have been involved in the murder of a senior magistrate, Ivo Cappo.
Mr Cappo was stoned to death at the end of October after driving into the camp of 87 Papuan refugees in front of the United Nations Refugee office in Port Moresby.
Four Papuans have been charged with murder and investigations are continuing, but chief inspector, Andy Bawa, says a police officer is now also being investigated.
"There is believed to be a police man also involved and he will be brought in for questioning. There is evidence that he was in some ways a part to the death of the late officer."
Chief inspector, Andy Bawa, says no court date has been confirmed and the motive of the killing is still unclear.
He says the 83 Papuan refugees are still seeking shelter at the police station but the situation there is getting dire.