Papua New Guinea Police say there is "unfinished business" in the country's highlands as they prepare to pursue the criminals who took an Australian professor and three local women hostage.
After more than a week in captivity, Bryce Barker and his PNG colleagues Teppsy Beni and Jemina Haro were freed on Sunday.
The three researchers and another team member, Cathy Alex, who was released three days earlier, had been completing fieldwork in a remote area near Mount Bosavi when they were taken hostage.
PNG's Prime Minister James Marape thanked those involved in securing the group's release but said: "The success is not yet complete."
"Police are still at work up there," he said.
"The first stage of the operation has been concluded, the second phase is simple: Those criminals, turn yourselves into the hands of police and make it easy for yourself."
He warned authorities would "not rest" until the matter was concluded.
"Let me tell all the criminals: Police firepower is always higher than criminal firepower," he said.
"I will not tolerate this kind of nonsense anymore."
Hostages 'in good spirits' after ordeal
Mr Marape was at the airport to greet Professor Barker, Ms Haro and Ms Beni when they were flown into Port Moresby from the highlands.
He said he apologised to them for the ordeal.
"The horrendous experience that those four captives went through is a story that I don't want any friends of Papua New Guinea, or any Papua New Guineans, to experience again," Mr Marape said.
The country's police commissioner, David Manning, said they were "in good spirits when we picked them up" and were given immediate medical checks.
"It is quite a traumatic experience for anyone — regardless of if you are an expatriate or a Papua New Guinean," he said.
Professor Barker, who is an Australian resident and New Zealand citizen, arrived in Cairns on Monday afternoon ahead of a flight to Toowoomba.
Mr Manning said the group would be given time to "process what has happened, come to terms with what has happened and of course be surrounded by their loved ones to assure them that everything is OK".
'We could not risk a life'
The gang that took the hostages is from Komo in Hela Province. Authorities say more than a dozen members have already been identified.
The criminals initially demanded a ransom of 3.5 million kina ($1.5 million) in exchange for releasing the hostages.
A far smaller amount was eventually paid during negotiations over Saturday and Sunday.
The ABC understands two separate payments were made to secure their release.
"We reached a stage in the operation where we felt we could not delay anymore, they had to come out," Mr Marape said.
Mr Marape said authorities could have taken an alternate course of action, noting that security forces were "within sight of the place where the hostages were held", but it was deemed too risky for the hostages.
"Engagement was possible, security and lives of these three were still at risk … we had to secure them out alive," he said.
"We could not risk a life."
Dozens of heavily armed police and defence personnel have been flown into the area in recent days. It is understood they have the area where the criminals have been hunkering down surrounded.
Mr Manning said negotiating the release of the hostages was always the first option.
"The result does not negate the criminality that was involved," he said.
"[We are] very much committed to ensuring that those who are responsible are held to account."
Local villagers fear ongoing risks
Kidnappings for ransom remain rare in Papua New Guinea, and security personnel are focused on not allowing this scenario to set a precedent for would-be copycats.
The successful pursuit of the criminals involved is seen as essential, not only for the conclusion of this case but for PNG's broader security.
"The operation continues to ensure that those who engage in criminal enterprise by the barrel of the gun face the laws of our country," Mr Marape said.
The gang involved has long been terrorising villages in the Mount Bosavi region, and many locals are concerned they may face retribution for assisting authorities to secure the release of the captives.
Mr Marape conceded the region had been a "dark space" in terms of accessibility and policing, but he said police and defence forces would remain on the ground to secure the area.
It is not only a law-and-order issue but also a political one for Mr Marape.
While the plane was in the air bringing Professor Barker and his colleagues back to Port Moresby, the arrival terminal changed, seemingly to allow the prime minister to welcome the group and give a press conference.
There was a brief traffic jam as police, diplomatic and media vehicles quickly moved locations.
Mr Marape was keen to emphasise a recent increase in funding for police, and to state his hard-line approach to criminal activity.
The New Zealand and Australian high commissioners were also at the airport for the arrival, and thanked PNG security forces and government for securing their release.
"It's a big relief to the hostages themselves and for their families in Papua New Guinea, in New Zealand and in Australia," New Zealand High Commissioner Phillip Taula said.
Australian archaeologist returns home
Professor Barker touched down in Toowoomba on Monday night and was met at the airport by staff from the University of Southern Queensland.
USQ vice-chancellor Geraldine Mackenzie spoke briefly at Wellcamp Airport after Professor Barker arrived, and said it had "been a long week".
"When we found out on Sunday that he was safe, it was the most enormous sense of relief that I think I have ever experienced in my life," she said.
"Bryce is a remarkable researcher and somebody who is a real leader in his field.
"We're supporting him as much as possible in this time and we really need for him to be able to do that in privacy, while he's recovering from this ordeal."
Queensland archaeologist Leanne Bateman has known Professor Barker for about a decade — he taught her during her undergraduate degree in 2013 and was her PhD supervisor in 2021.
"Bryce's passion was really in Papua New Guinea. He has had extensive experience with the people of [PNG]," Dr Bateman said.
"He had always worked in the most remote areas for decades."
She said while he would have had a lot of support from outside groups during the ordeal, "he would have kept communicating with kidnappers to save the lives of the small team that was with him".
"The hardest thing for him would have been harm to his team, because I know he would have been absolutely devastated if anything had happened to them," Dr Bateman said.
"He's a very good talker, a very good negotiator and very influential. I'm just so glad everyone got out safely and I hope everyone's going to be OK after this."
Dr Bateman said Professor Barker was very aware of the dangers that came with his remote work.
"He was always dropped in by helicopter to the most remote areas … where [quite often] people had never even seen a white man before," she said.
"With changing times, it's going to be a problem that may increase. It'll be interesting to see what his view will be whether he will return after this has happened."
