A New Zealand archeologist and his research team have been rescued through “covert operations” after they were taken for ransom by a criminal group in a remote part of Papua New Guinea last week, according to local officials.

Bryce Barker, a New Zealand Archeologist and professor at the University of Southern Queensland, was working alongside three local researchers and two guides in the remote highlands around Mount Bosavi when the group was kidnapped at gunpoint by an unspecified criminal gang last sunday. While in captivity, Barker made calls to local missionaries relaying the gang’s demands of a 3.5m Papua New Guinean Kina ($994,000) ransom for their release, according to the Australian outlet ABC News. By this time, the captors decided to release the two guides, however, one was said to have stayed with Barker and his team.

As word got out about the ransom, local authorities and military forces assembled a team to track down and rescue the hostages. According to ABC, poor weather and difficult terrain caused delays in sending teams to the remote areas, which was made harder by the gang frequently moving the hostages between villages.

On Wednesday, Cathy Alex, a program coordinator for Barker’s team, was released without ransom and returned to the village of Fogoma’iu. Alex, weak from lack of food and traversing the jungles of the region, passed along to authorities that the gang were still seeking a ransom for Barker and the rest.

Today, Papua New Guinea Prime Minister James Marape announced on Facebook that Barker and the two remaining members of his team were “returned through covert operations with no K3.5m paid.” It remains unclear what exactly happened and if any of the captors were captured. PNG’s Police Commissioner David Manning told ABC that “As far as police, and our security partners, the defense force and others, we still have some unfinished business..”