POLICE POWERLESS, MINISTER SILENT

TIM PALMER: The powerlessness or unwillingness of police in Papua New Guinea in the face of violence against people accused of black magic has been demonstrated again in yet another brutal killing.

A women accused of sorcery has been beheaded on the island of Bougainville.

Her murderers are also detaining three other people but local police say they don't have the manpower or the firepower to do anything about it.

The human rights group Amnesty International says that's not good enough and is demanding the police do their jobs.

PNG correspondent Liam Fox reports.

LIAM FOX: It's hard to imagine that police would respond to the kidnapping of four people and the subsequent murder of one of them, by throwing their hands up in defeat. But that is exactly what's happening in the south of Bougainville.

Paul Kamuai is the acting assistant police commissioner for the region.

PAUL KAMUAI: In this situation it was a very extraordinary situation that men and women were there and it was at night and then we found out that there were arms around and we couldn't use the arms, so there would be a lot of killings from the police and then from the civilians as well.

LIAM FOX: Last Tuesday two women, Helen Rumbali and her sister Nikono and the Nikonos' two teenage daughters were kidnapped by an armed mob and taken to Lopele village in the Bana district.

The women were accused of using sorcery or black magic to kill someone and they were tortured for several days. Then on Friday the mob murdered Helen Rumbali by cutting her head off.

After negotiations with community leaders the mob allowed Nikono and her daughters to go to a local health clinic but they've set up a roadblock preventing them from leaving the area.

Nikono Rumbali is believed to be in a critical condition after the mob tried unsuccessfully to decapitate her.

Assistant commissioner Kamuai says police have no immediate plans to try and rescue the trio or arrest the murderers. He says they're outnumbered and outgunned.

PAUL KAMUAI: Police on Bougainville are not armed. Even if we are armed there is more arms still out there. I have eight regular police. They do not have a proper police station. They live in the villages so we can't very quickly get them in to act in a group.

LIAM FOX: It's a common problem. Across PNG police lack the resources and manpower to keep the peace.

But on Bougainville they face an added problem. The island is awash with guns, a hangover of the bitter civil war fought there during the 1990s.

The fighting ended with a peace agreement in 2001 but disarmament efforts have stalled and there are plenty of factory and home-made weapons in the hands of ex-combatants and others.

Despite those difficulties, Amnesty International says the police response, or lack thereof, is not good enough.

KATE SCHUETZE: If all the police can do is stand by and watch while women are executed that's a very sad situation for the country indeed.

LIAM FOX: Kate Schuetze is Amnesty International's Pacific researcher and she says the PNG government must provide police with the resources they need to do their jobs.

KATE SCHUETZE: I understand that there are limitations with resources but it's not an adequate excuse for government to say that they can't protect someone's life and meet their responsibilities that they've signed up to, just because they don't have the capacity.

LIAM FOX: Sadly, sorcery killings are not uncommon in PNG.

In February a woman who was burnt alive on a street in Mt Hagen, the biggest town in PNG's highlands, made headlines around the world.

But Bougainvilleans say the murder of Helen Rumbali is the first sorcery killing on their island.

Helen Hakena from the North Bougainville Human Rights Committee believes the murderers have used sorcery as a cover for other motives.

HELEN HAKENA: It's pure jealousy of a family who is well known, that they've got positions in government and this woman is a woman leader and they've got good homes.

LIAM FOX: Ms Hakena says Bougainvillean women are horrified at what has happened and they too want the police to take action.

HELEN HAKENA: If this one woman is not respected then all of us will face the same consequences too in the hands of our sons here.

LIAM FOX: But it's not only the police that are standing by doing nothing.

When the ABC contacted Steven Kamma, the Minister for Bougainville Affairs, he declined to comment, saying he didn't want to get involved.

This is Liam Fox in Port Moresby reporting for PM. - ABC