An Australian academic says sorcery-related killings in Papua New Guinea are still largely hidden.
The comment follows a conference in Goroka on how to stop a rising number of attacks on people accused of sorcery.
A senior research fellow at the Australian National University says the violence is spreading to areas where it has not been a traditional part of the culture and much of the time it is escaping the notice of the authorities.
Richard Eves says he has interviewed some Eastern Highlands men who killed five women.
"Chopped a number of them up and put them into bags and threw them into a river. The six perpetrators who were actually arrested spent two-and-a-half years in jail. So obviously the police for a start aren't finding out about these things, they're hidden, they're out in the communities. That's why I say it's almost a silent epidemic."
Richard Eves says one of the men he has interviewed has killed 20 women in five separate attacks.