Papua New Guinea police say police intelligence suggests that two women scientists missing since 2011 are alive but held captive in West New Britain province.
The women were part of a group of five scientists and two local tour operators who vanished while on a study field trip in the waters off West New Britain.
The deputy Police Commissioner Operations, Simon Kauba, says he has been briefed by his men that they are working on concrete information that will shed light on the mystery.
He has also appealed to the people living in the area to assist his men instead of hiding behind their culture and customs.
Mr Kauba says there are strong suggestions that the women are held captive by people loyal to former escaped prisoner, Don Aka, and have customarily pledged to keep quiet about their captives.
Aka was recaptured about a month ago.