(G.Miranda/Funai/Survival International)

The outside world might never have heard about the suspected massacre if not for some barroom boasting by a group of miners fresh from working an illegal gig in the Amazon jungle.

The garimpeiros had bragged that they’d come across members of a reclusive, uncontacted Amazonian tribe near Brazil’s border with Peru and Colombia, authorities say.

The tribe members were greater in number — there were as many as 10 — but the gold miners said they’d gotten the better of them and killed the entire lot, said Carla de Lello Lorenzi, communications officer for Survival International in Brazil.

The miners cut the tribe members’ bodies so that they wouldn’t float, Lorenzi said, then dropped them into the Jandiatuba River.

The miners had collected tools and jewelry from the indigenous dead, corroborating their story.

An unidentified person who overheard the story was disturbed by it, recorded the miners’ conversation and turned the audio over to authorities. They have since launched an investigation into what, if confirmed, would be one of the largest mass murders of uncontacted people in decades.

Advocates for stricter protective measures say the suspected massacre is evidence that the Brazilian government isn’t doing enough to safeguard the more than 100 vulnerable tribes that have never made contact with the outside world — and have no desire to.

“If these reports are confirmed, [Brazilian President Michel Temer] and his government bear a heavy responsibility for this genocidal attack,” said Survival International’s director, Stephen Corry. Corry said the government has slashed funds for an agency that protects the tribes, leaving them “defenseless against thousands of invaders — gold miners, ranchers and loggers — who are desperate to steal and ransack their lands.”

“All these tribes should have had their lands properly recognized and protected years ago — the government’s open support for those who want to open up indigenous territories is utterly shameful, and is setting indigenous rights in Brazil back decades.”

According to the New York Times, the government closed five of the 19 bases it uses to monitor uncontacted tribes and prevent incursions by miners and loggers.

Three of the closed bases were in the Javari Valley, home to more uncontacted tribes than anywhere else on Earth.

For obvious reasons, little is known about the indigenous group involved in the suspected killings.

Locally, Lorenzi said, they’re known as Fleicheros, or “the ones who throw arrows,” but their language and customs — and how they interact with at least two other uncontacted tribes in the immediate area — remain a mystery.

But the tribe members are not the only people in that part of the Amazon, Lorenzi said. It is illegal to mine there, but prospectors have brought earth-moving equipment to the area, leaving giant craters that can be seen from the sky.

They also bring violence, according to the government, which says garimpeiros are responsible for threats, child prostitution and killings.

Even their nonviolent presence in the protected lands can be dangerous to uncontacted tribes, which lack the immunity to fight the diseases that miners and loggers bring.

Any contact can be contentious and even violent, with the uncontacted usually getting the worst of it because, as Lorenzi told The Post, “it’s usually bows and arrows against guns.”

Details about those contacts remain hazy, because they involve two groups of people unlikely to speak to authorities.

Still, tales of the worst violence sometimes get out. Survival International documented the story of Marisa Yanomami and Leida Yanomami, survivors of the Haximu massacre in 1993:

“The gold-miners killed our brothers and sisters and also killed our father with machetes; some of them were killed with guns,” they told the organization. “After the first 10 people died, at the start of the war, we moved to another place to hide and stayed in our shabono (communal house), but the next day, the miners appeared again.”

In a statement on its website, the Brazilian National Indian Foundation, or Funai, said it had prompted the federal public prosecutor’s office to investigate the most recent allegation.

The government has also trumpeted its latest operation against incursions on protected lands. In August, it shut down an illegal mining operation. Soldiers destroyed four dredging machines and fined mining operators $1 million for environmental crimes.

[A rare and elusive white moose has finally been captured on video]

Investigations are tough undertakings. The site of the suspected killing, for example, is a 12-hour trek by boat during the dry season. And it involves a group of people with their own language and a centuries-long wariness of outsiders.

Even the details of the killing are sketchy, Lorenzi said. And the vacuum of information speaks to another fear advocates have: that these types of violent interactions happen a lot more frequently than is reported.

“That’s highly probable, yes, because it’s so difficult to document,” she said. “It’s the uncontacted versus illegal miners who think they can get away with anything.

“Unfortunately, a lot of the time they do.”

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Shortly after Stephen K. Bannon, President Trump’s former chief strategist, finished taping his “60 Minutes” interview, a top Bannon aide texted White House Communications Director Hope Hicks to enthuse about the upcoming show. Bannon, the aide wrote, had offered an “epic” defense of the president, according to three people with knowledge of the exchange.

But after the interview aired Sunday evening on CBS, the reality was a bit more complicated.

Bannon did offer forceful praise — and, indeed, an epic defense — of Trump and much of his agenda. But he also called Trump’s decision to fire FBI Director James B. Comey the biggest mistake “maybe in modern political history”; accused Republican congressional leaders of “trying to nullify the 2016 election”; and warned that the president’s decision to give Congress six months to come up with a solution for “dreamer” immigrants brought to the country illegally as children could cause a “civil war” within the Republican Party.

In her daily press briefing Monday, White House spokeswoman Sarah Huckabee Sanders seemed to distance the administration from the man who had served as Trump’s ideological id and keeper of his nationalist campaign promises. 

Sanders said that “the president was right in firing Director Comey,” and pushed back on some of Bannon’s other assertions. “I think that Steve always likes to speak in, kind of, the most extreme measures,” she said.

Bannon’s impassioned interview with Charlie Rose on “60 Minutes,” and the White House’s more muted public response, underscored the complicated relationship between Trump and his former chief strategist, who has returned to a more public perch from which to fire salvos — Breitbart News, the conservative website, where he serves as executive chairman. 

Bannon has cast himself as a loyal Trump soldier, attacking only the president’s obvious enemies who need to be “put on notice,” as he told Rose. But Bannon has at times also treated Trump as an imperfect vehicle for his own nationalist agenda, chafing at the advisers and family members the president brought in who did not share that vision. On the day he left the White House last month, Bannon told the Weekly Standard, “The Trump presidency that we fought for, and won, is over.”

“It’s difficult to make the case that you’re helping the president if you’re in the position where you’re actively opposing either him or his political agenda,” said Ryan Williams, a Republican strategist. “That’s a fine line for Mr. Bannon to walk, despite the fact that he may agree with the president on many issues.”

For now, however, the president is pleased with Bannon’s most recent star turn. Trump watched the “60 Minutes” interview and liked it, telling friends and aides he was appreciative of the praise Bannon offered for him and his policies, according to one person familiar with the president’s thinking. 

“He thought that it was an articulate and forceful defense of him, as well as a very strong and very intelligent positioning of some of the core issues of the administration,” said this person, who insisted on anonymity to offer a candid recounting of the president’s comments. 

Within the West Wing, reviews of Bannon’s interview were mixed. Some were exasperated by the mere fact of it, griping that the rumpled strategist is disingenuously trying to have it both ways — claiming he supports the president’s agenda while really pushing his own. But others were ebullient, saying Bannon came off as both smart and authentic, all while defending Trump. 

The president has felt conflicted about Bannon since the early months of the administration, when Bannon’s rising public profile — he appeared on the cover of “Time” as “The Great Manipulator” — began bothering Trump. 

The president is worried about potential mischief-making from Bannon outside the White House, especially in causing problems for the president with his base. Trump also dislikes what he sees as Bannon profiting off him or getting undue credit for his presidential victory. Trump has been quick to point out — publicly and privately — that he dispatched an entire field of GOP primary challengers before Bannon joined the campaign in August 2016. 

Already, fault lines between the two men have begun to show. Bannon has declared war on the Republican establishment and is working to help primary challenges against GOP senators he views as disloyal or insufficiently conservative. Trump recently moved in a different direction, cutting a deal last week with Democrats to raise the debt ceiling, fund the government and provide Hurricane Harvey relief. And should the president’s detente with Democrats falter, he may yet find he needs the very Republicans — and Republican leaders — with whom Bannon is feuding.

In the “60 Minutes” interview, Bannon said he worried that Trump’s decision to delay an end to Barack Obama’s Deferred Action for Childhood Arrivals, or DACA, program could cause Republicans to lose their House majority. Bannon added that he hoped “dreamers,” as program recipients are called, will “self-deport,” saying that “amnesty is nonnegotiable.”

Trump, meanwhile, has pressed Senate Minority Leader Charles E. Schumer (D-N.Y.) in private conversations for a trade — exchanging dreamer protections for funding for a border wall, even though Democrats have said wall funding is a non-starter, according to someone familiar with the discussions.

And in the Alabama Senate primary, the president has endorsed Sen. Luther Strange (R-Ala.) — the top choice of Senate Majority Leader Mitch McConnell (R-Ky.) — while Bannon and Breitbart are backing conservative jurist Roy Moore. Bannon allies note, however, that even when Breitbart has been critical of Strange, the site has not attacked the president himself. 

Bannon took the “60 Minutes” interview seriously, people close to him said, even working through sample questions in advance to prepare. His only goal, friends said, was to defend the president, while also making a point not to get drawn into named attacks on some of his rivals inside the White House — including Jared Kushner, Trump’s son-in-law and senior adviser, and H.R. McMaster, the national security adviser. The one major exception was Gary Cohn, director of the National Economic Council, who Bannon said should have resigned from the administration after criticizing the president publicly over his response to white supremacist violence in Charlottesville. 

Trump and Bannon still enjoy a close relationship. In her briefing Monday, Sanders said they have had “one conversation” since he left the White House, though Bannon confidants say they suspect that number is higher. 

At the “Breitbart Embassy” — a Capitol Hill townhouse that serves as the office for Bannon and his website — and within his broader orbit, there was excitement bordering on elation over the interview. 

“Steve went into one of the most high-profile venues possible, ‘60 Minutes,’ and defended the president’s agenda and campaign pledges, and he also then gave insight into how the president is being undermined by Republican leadership,” said Sam Nunberg, a former Trump adviser. “It seemed to be courageous.”