MANAUS, BRAZIL -- A fisherman confessed to killing a British journalist and an Indigenous expert in Brazil's remote Amazon region and took police to a site where human remains were recovered, a federal investigator said after a grim 10-day search for the missing pair.

Authorities said they expected to make more arrests in the case of freelance reporter Dom Phillips and Bruno Pereira of Brazil, who disappeared June 5. None had been made as of Thursday, but police said a search for the boat the two had used was restarting.

They gave no immediate explanation of a motive for the killing, but officials earlier suggested that Pereira's work to stop illegal fishing in an Indigenous reserve had angered local fishermen.

Two federal police officials in the capital, Brasilia, told The Associated Press on Thursday that a total of five people were being investigated, including the fisherman who confessed and his brother who was detained Tuesday as a suspect. The officials, who spoke on condition of anonymity because they were not authorized to speak publicly about the investigation, provided no further details.

At a news conference Wednesday night in the Amazon city of Manaus, federal police investigator Eduardo Alexandre Fontes said the prime suspect in the case, 41-year-old Amarildo da Costa de Oliveira, told officers he used a firearm to kill the men.

"We would have no way of getting to that spot quickly without the confession," Torres said of the place where police recovered human remains Wednesday after being led there by de Oliveira, who is nicknamed "Pelado."

"We found the bodies 3 kilometers (nearly 2 miles) into the woods," the investigator said, adding that officers traveled about one hour and forty minutes by boat and 25 more into the woods to reach the burial spot.

Torres said the remains were expected to be identified within days, and if confirmed as the missing men, "will be returned to the families of the two." A federal police plane flew the remains into Brasilia on Thursday evening, and officials said testing would begin Friday.

The suspect's family had said previously that he denied any wrongdoing and claimed police tortured him to try to get a confession.

Another officer, Guilherme Torres of the Amazonas state police, said the missing men's boat had not been found yet but police knew the area where it purportedly was hidden.

"They put bags of dirt on the boat so it would sink," he said. The engine of the boat was removed, according to investigators.

Pereira had been on leave from Brazil's National Indian Foundation, the government agency in charge of protecting Indigenous people.

He "leaves an immense legacy for the policies of protection of uncontacted and recently contacted Indigenous peoples," the agency, known as FUNAI, said in a statement, calling him "one of the country's main experts" on the issue.

"He was considered to be a reference for colleagues and Indigenous peoples, with whom he built a friendship relationship over the years."

President Jair Bolsonaro sent a tweet Thursday saying, "Our condolences to family members and may God comfort everyone's heart.

Bolsonaro has been a frequent critic both of journalists and Indigenous experts and his government was accused of being slow to act in the disappearances. Before the bodies were discovered on Wednesday, he criticized Phillips in an interview, saying that locals in the area where he went missing didn't like him and that he should have been more careful in the region.

UNIVAJA, an association of Indigenous peoples of the Javari Valley, mourned the loss of "two partners" in a statement Wednesday, adding they only had help and protection from local police.

Pereira, 41, and Phillips, 57, were last seen on their boat in a river near the entrance of the Javari Valley Indigenous Territory, which borders Peru and Colombia. That area has seen violent conflicts between fishermen, poachers and government agents.

Indigenous people who were with Pereira and Phillips have said that Pelado brandished a rifle at them on the day before the pair disappeared.

On Sunday, searchers found a backpack, laptop and other personal belongings submerged underwater in the Itaquai river. The find was near a spot where a day earlier volunteers from the Matis Indigenous group found a tarp from the missing men's boat.

Officials previously reported finding traces of blood in Pelado's boat. The federal police said Thursday analysis of the blood showed it wasn't from Phillips but the tests were "inconclusive" concerning Pereira. It said further tests would be conducted.

Authorities have said a main line of investigation has pointed to an international network that pays poor fishermen to fish illegally in the Javari Valley reserve, which is Brazil's second-largest Indigenous territory.

Pereira, who previously led FUNAI's local office in the region, had taken part in several operations against illegal fishing. which usually lead to seizure of fishing gear and fines for violators. Only the Indigenous can legally fish in their territories.

But police have not ruled out other motives, such as drug trafficking.

Phillips' wife, Alessandra Sampaio, said late Wednesday that the discovery of bodies "puts an end to the anguish of not knowing Dom and Bruno's whereabouts."

"Now we can bring them home and say goodbye with love," Sampaio said in a statement. "Today, we also begin our quest for justice."

Pereira's wife, Beatriz Matos, expressed her grief ohursday.

"Now that Bruno's spirits are strolling in the forest and spread on us, our strength is much bigger," she said on Twitter.

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Savarese reported from Sao Paulo.

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Associated Press writer Debora Alvares in Brasilia contributed to this report.