The police commander in the Papua New Guinea province of Bougainville says they are still to make arrests for the killing of a woman, who earlier this month was accused of sorcery in Bana in the south of the province.
The woman, a school teacher and human rights activist, Helen Rumbali, was decapitated.
She had been kidnapped with three female colleagues who were hurt.
The three were given care at a local health clinic but have been moved to Buka Hospital after police removed road blocks set up by the kidnappers.
Commander Paul Kamuai says a composite team of police, community constables and some ex-combatants will make a full investigation before any arrests are made.
"There's a wilful murder been committed; there's serial kidnapping; there's roadblocks set up; there's been use of firearms - those sort of things that is why police really need to get their evidence right before they can start making their arrests. That is why I am saying the investigation is underway."
Paul Kamuai says police have also been working with a peace building team planning traditional reconciliations between the kidnappers and the families of the women accused of sorcery.