Madeline Peltz works the night shift at the liberal media watchdog group Media Matters for America. Given the timing of that particular shift, one of her main responsibilities is watching Tucker Carlson's 8pm show on Fox News.

And she has watched a lot of Tucker Carlson.

Mr Carlson has been in the public eye for some 20 years - first as a print journalist, then a television commentator, founder of the conservative site the Daily Caller, and now, Fox News host, with a prime time slot and a salary in the millions. But people have been confused by Mr Carlson's tone on Fox since he took over for Bill O'Reilly in 2018, noting concern about diversity and demographics in his show.

After many Carlson-watching hours, the 24-year-old researcher developed a working theory, which she outlined on the nonprofit's website: that Mr Carlson is using his platform on Fox News to introduce white nationalist ideas to the mainstream, making him a uniquely prominent "mouthpiece for white supremacy."

Ms Peltz dug into his recent past and discovered a trove of appearances he made on shock jock Bubba the Love Sponge's radio show between 2006 and 2011. She found a series of misogynistic, racist and homophobic remarks Mr Carlson made, the audio of which Media Matters published this week.

World news in pictures Show all 50 1 /50 World news in pictures World news in pictures 14 September 2020 Japan's Prime Minister Shinzo Abe, Chief Cabinet Secretary Yoshihide Suga, former Defense Minister Shigeru Ishiba and former Foreign Minister Fumio Kishida celebrate after Suga was elected as new head of the ruling party at the Liberal Democratic Party's leadership election in Tokyo Reuters World news in pictures 13 September 2020 A man stands behind a burning barricade during the fifth straight day of protests against police brutality in Bogota AFP via Getty World news in pictures 12 September 2020 Police officers block and detain protesters during an opposition rally to protest the official presidential election results in Minsk, Belarus. Daily protests calling for the authoritarian president's resignation are now in their second month AP World news in pictures 11 September 2020 Members of 'Omnium Cultural' celebrate the 20th 'Festa per la llibertat' ('Fiesta for the freedom') to mark the Day of Catalonia in Barcelona. Omnion Cultural fights for the independence of Catalonia EPA World news in pictures 10 September 2020 The Moria refugee camp, two days after Greece's biggest migrant camp, was destroyed by fire. Thousands of asylum seekers on the island of Lesbos are now homeless AFP via Getty World news in pictures 9 September 2020 Pope Francis takes off his face mask as he arrives by car to hold a limited public audience at the San Damaso courtyard in The Vatican AFP via Getty World news in pictures 8 September 2020 A home is engulfed in flames during the "Creek Fire" in the Tollhouse area of California AFP via Getty World news in pictures 7 September 2020 A couple take photos along a sea wall of the waves brought by Typhoon Haishen in the eastern port city of Sokcho AFP via Getty World news in pictures 6 September 2020 Novak Djokovic and a tournament official tends to a linesperson who was struck with a ball by Djokovic during his match against Pablo Carreno Busta at the US Open USA Today Sports/Reuters World news in pictures 5 September 2020 Protesters confront police at the Shrine of Remembrance in Melbourne, Australia, during an anti-lockdown rally AFP via Getty World news in pictures 4 September 2020 A woman looks on from a rooftop as rescue workers dig through the rubble of a damaged building in Beirut. A search began for possible survivors after a scanner detected a pulse one month after the mega-blast at the adjacent port AFP via Getty World news in pictures 3 September 2020 A full moon next to the Virgen del Panecillo statue in Quito, Ecuador EPA World news in pictures 2 September 2020 A Palestinian woman reacts as Israeli forces demolish her animal shed near Hebron in the Israeli-occupied West Bank Reuters World news in pictures 1 September 2020 Students protest against presidential elections results in Minsk TUT.BY/AFP via Getty World news in pictures 31 August 2020 The pack rides during the 3rd stage of the Tour de France between Nice and Sisteron AFP via Getty World news in pictures 30 August 2020 Law enforcement officers block a street during a rally of opposition supporters protesting against presidential election results in Minsk, Belarus Reuters World news in pictures 29 August 2020 A woman holding a placard reading "Stop Censorship - Yes to the Freedom of Expression" shouts in a megaphone during a protest against the mandatory wearing of face masks in Paris. Masks, which were already compulsory on public transport, in enclosed public spaces, and outdoors in Paris in certain high-congestion areas around tourist sites, were made mandatory outdoors citywide on August 28 to fight the rising coronavirus infections AFP via Getty World news in pictures 28 August 2020 Japanese Prime Minister Shinzo Abe bows to the national flag at the start of a press conference at the prime minister official residence in Tokyo. Abe announced he will resign over health problems, in a bombshell development that kicks off a leadership contest in the world's third-largest economy AFP via Getty World news in pictures 27 August 2020 Residents take cover behind a tree trunk from rubber bullets fired by South African Police Service (SAPS) in Eldorado Park, near Johannesburg, during a protest by community members after a 16-year old boy was reported dead AFP via Getty World news in pictures 26 August 2020 People scatter rose petals on a statue of Mother Teresa marking her 110th birth anniversary in Ahmedabad AFP via Getty World news in pictures 25 August 2020 An aerial view shows beach-goers standing on salt formations in the Dead Sea near Ein Bokeq, Israel Reuters World news in pictures 24 August 2020 Health workers use a fingertip pulse oximeter and check the body temperature of a fisherwoman inside the Dharavi slum during a door-to-door Covid-19 coronavirus screening in Mumbai AFP via Getty World news in pictures 23 August 2020 People carry an idol of the Hindu god Ganesh, the deity of prosperity, to immerse it off the coast of the Arabian sea during the Ganesh Chaturthi festival in Mumbai, India Reuters World news in pictures 22 August 2020 Firefighters watch as flames from the LNU Lightning Complex fires approach a home in Napa County, California AP World news in pictures 21 August 2020 Members of the Israeli security forces arrest a Palestinian demonstrator during a rally to protest against Israel's plan to annex parts of the occupied West Bank AFP via Getty World news in pictures 20 August 2020 A man pushes his bicycle through a deserted road after prohibitory orders were imposed by district officials for a week to contain the spread of the Covid-19 in Kathmandu AFP via Getty World news in pictures 19 August 2020 A car burns while parked at a residence in Vacaville, California. Dozens of fires are burning out of control throughout Northern California as fire resources are spread thin AFP via Getty World news in pictures 18 August 2020 Students use their mobile phones as flashlights at an anti-government rally at Mahidol University in Nakhon Pathom. Thailand has seen near-daily protests in recent weeks by students demanding the resignation of Prime Minister Prayut Chan-O-Cha AFP via Getty World news in pictures 17 August 2020 Members of the Kayapo tribe block the BR163 highway during a protest outside Novo Progresso in Para state, Brazil. Indigenous protesters blocked a major transamazonian highway to protest against the lack of governmental support during the COVID-19 novel coronavirus pandemic and illegal deforestation in and around their territories AFP via Getty World news in pictures 16 August 2020 Lightning forks over the San Francisco-Oakland Bay Bridge as a storm passes over Oakland AP World news in pictures 15 August 2020 Belarus opposition supporters gather near the Pushkinskaya metro station where Alexander Taraikovsky, a 34-year-old protester died on August 10, during their protest rally in central Minsk AFP via Getty World news in pictures 14 August 2020 AlphaTauri's driver Daniil Kvyat takes part in the second practice session at the Circuit de Catalunya in Montmelo near Barcelona ahead of the Spanish F1 Grand Prix AFP via Getty World news in pictures 13 August 2020 Soldiers of the Brazilian Armed Forces during a disinfection of the Christ The Redeemer statue at the Corcovado mountain prior to the opening of the touristic attraction in Rio AFP via Getty World news in pictures 12 August 2020 Young elephant bulls tussle playfully on World Elephant Day at the Amboseli National Park in Kenya AFP via Getty World news in pictures 11 August 2020 French Prime Minister Jean Castex is helped by a member of staff to put a protective suit on prior to his visit at the CHU hospital in Montpellier AFP via Getty World news in pictures 10 August 2020 Locals harvest their potatoes as Mount Sinabung spews volcanic ash in Karo, North Sumatra province, Indonesia Antara Foto/Reuters World news in pictures 9 August 2020 Doves fly over the Peace Statue at Nagasaki Peace Park during the memorial ceremony held for the 75th anniversary of the atomic bombing EPA World news in pictures 8 August 2020 Anti-government protesters try to remove concrete wall that installed by security forces to prevent protesters reaching the Parliament square, during a protest against the political elites and the government after this week's deadly explosion in Beirut AP World news in pictures 7 August 2020 A protester throws a stone towards Israeli forces in the village of Turmus Aya, north of Ramallah in the occupied West Bank, following a march by Palestinians against the building of Israeli settlements AFP via Getty World news in pictures 6 August 2020 A woman yells as soldiers block a road for French President Emmanuel Macron's visit the Gemmayzeh neighborhood. The area in Beirut suffered extensive damage from the explosion at the seaport AP World news in pictures 5 August 2020 Damage at the site of Tuesday's blast in Beirut's port area, Lebanon Reuters World news in pictures 4 August 2020 A large explosion in the Lebanese capital Beirut. The blast, which rattled entire buildings and broke glass, was felt in several parts of the city AFP via Getty World news in pictures 3 August 2020 A general view shows the new road bridge in Genoa, Italy ahead of its official inauguration, after it was rebuilt following its collapse on August 14, 2018 which killed 43 people Reuters World news in pictures 2 August 2020 Empty stall spaces are seen hours before a citywide curfew is introduced in Melbourne, Australia EPA World news in pictures 1 August 2020 People take part in a demonstration by the initiative "Querdenken-711" with the slogan "the end of the pandemic - the day of freedom" to protest against the current measurements to curb the spread of COVID-19 in Berlin, Germany AFP via Getty World news in pictures 31 July 2020 Pilgrims circumambulating around the Kaaba, the holiest shrine in the Grand mosque in Mecca. Muslim pilgrims converged today on Saudi Arabia's Mount Arafat for the climax of this year's hajj, the smallest in modern times and a sharp contrast to the massive crowds of previous years Saudi Ministry of Media/AFP World news in pictures 30 July 2020 The Mars 2020 Perseverance mission lifts off at the Kennedy Space Centre in Florida. The mission is part of the USA's largest moon to Mars exploration. Nasa will attempt to establish a sustained human presence on and around the moon by 2028 through their Artemis programme EPA World news in pictures 29 July 2020 A woman refreshes herself in a outdoor pool in summer temperatures in Ehingen, Germany dpa via AP World news in pictures 28 July 2020 Malaysia's former prime minister Najib Razak speaks to the media after he was found guilty in his corruption trial in Kuala Lumpur AFP via Getty World news in pictures 27 July 2020 North Korean leader Kim Jong Un poses for a photograph after conferring commemorative pistols to leading commanding officers of the armed forces on the 67th anniversary of the "Day of Victory in the Great Fatherland Liberation War". Which marks the signing of the Korean War armistice KCNA via Reuters

In response, Mr Carlson was defiant, casting himself as the victim of "the great American outrage machine," a mob of power-seeking organisations and people that he says are waging a political war to censor him.

In reality, credit for the tapes' publication is due to Ms Peltz: a 20-something in her first adult job who lives in the basement of a Washington, DC, house she rents with five other people, a few cats and a dog named Noodles.

"I'm not like some high-power wielding globalist," Ms Peltz said, adopting the conspiracy-inflected jargon of the far right. "I'm this kid who's been on the Internet my whole life and knows how to get around it."

It has been a busy week at Media Matters, which tracks conservative media trends and has engaged in a years-long effort to cast light on the ways Fox News and its hosts sidestep traditional journalism guidelines.

The organisation released the first audio of Mr Carlson on Sunday. In that, Mr Carlson called rape shield laws "totally unfair" and was adamantly supportive of Warren Jeffs, the former leader of the Fundamentalist Church of Jesus Christ of Latter-day Saints who is serving a life sentence for child rape. Mr Carlson also said he would "love" a scenario involving young girls sexually experimenting and described women as "extremely primitive."

The next day, Media Matters for America released another audio file just moments after Mr Carlson's show began. In that, Mr Carlson said that white men deserve credit for "creating civilization," called Iraqis a bunch of "semiliterate primitive monkeys," and spoke about his desire for a presidential candidate to blame the "lunatic Muslims who are behaving like animals."

There was more on Tuesday. This time, Mr Carlson could be heard joking about having sex with what he thought was an underage beauty pageant contestant.

On his Tuesday night show, Mr Carlson did not address the audio itself. Instead, he took aim at Media Matters, calling it "a George Soros-funded lobbying organisation whose sole mission is to punish critics of the Democratic Party."

But the tapes have turned up pressure on the show, teeing off an advertiser boycott and a protest in front of Fox News's headquarters in New York City on Wednesday, which Media Matters helped organise.

When asked for a comment for this story, Fox News spokesperson Carly Shanahan pointed to Mr Carlson's statements on his show this week.

Media Matters for America is not currently funded by George Soros; he has not donated to the organisation in many years, its president, Angelo Carusone, said in an interview.

While Mr Carlson described it as working to "bully" corporations, it is the fraction of the size of Fox News, whose revenue for 2018 has been estimated to be more than $3bn (£2.3bn). Media Matters has about 80 employees and a budget of about $14m (£10.6m) that mostly comes from private donors, Mr Carusone said.

Tucker Carlson makes sexist and misogynistic comments in unearthed recording

The group does media analysis from a left-leaning perspective, studying trends and themes to see how political discussions play out in the nation's media bubbles. Its staff monitors some 50,000 of live programming on television and radio every year and the organisation tapes another million hours of audio and video on top of that.

Media Matters, which has an active website that highlights and contextualises some of these moments, drew criticism during the 2016 for what some saw as an attempt to malign coverage that was critical of Hillary Clinton. But it has found a renewed prominence in the Trump era by turning its sights to the new information economy: the rise of conspiracy theories and misinformation online, the increased visibility of fringe right-wing websites and ideas, and an energised conservative media ecosystem that helps amplifies those ideas - an news cycle that often peaks with a tweet from President Donald Trump.

"When we did a power mapping of the landscape at the end of 2016 early 2017, what we found was that so much of what used to be dismissed as the fringes was now where power was being organised: 4chan; Daily Stormer comment sections; subreddits," Mr Carusone said. "These would never have been considered worthy enough or important enough to monitor [before]. But we looked at it and they were - they were driving a lot of the misinformation and fake news of 2016. They were creating a lot of material that was making it onto Fox News or Donald Trump's Twitter feed."

Mr Carusone said the organisation had to build some new digital technology to track the online conversations in forums and message boards that he said have such a large effect on the political discourse in the United States.

"It's basically it's just a giant DVR for the 'chans, an archive of these message boards," Mr Carusone said.

And it has been doing studies and using other data to advocate for better practices. It pushed Google to stop allowing what it had assessed as fake news-purveying websites to use the company's AdSense program. It has met with the big three technology companies - Facebook, Google and Twitter – Mr Carusone said, but said NDAs prevented him from disclosing more about that. It also works with journalists to publicise problems or issues when other methods of persuasion fail.

"It's a combination of building up public pressure or direct lobbying," Mr Carusone said.

Ms Peltz's project was her idea, Mr Carusone said. And he said the organisation decided to publish portions of what she had found after deciding it was relevant to understanding Mr Carlson's current political views.

"We didn't just try to embarrass him," Mr Carusone said. "We took things that directly echo his show now, and things that had some relevancy today."

Tucker Carlson makes sexually explicit jokes about Miss Teen USA contestant in latest audio

Mr Carlson has responded by attacking Media Matters for America, along with the Southern Poverty Law Centre, whose categorisation of hate groups is used widely by media organisations.

He has also been engaged in a long-running feud with CNN; on Tuesday he called anchor Brian Stelter a "eunuch," multiple times, name-calling that was omitted from the text of his monologue later posted on the Fox News website.

"This is what an authoritarian society looks like," Mr Carlson said. "It was only a matter of time before they came for Fox News."

He also took aim at Media Matters' designation as a tax-exempt nonprofit and urged viewers to call the IRS.

"In its original tax application to the IRS, Media Matters claimed that the American news media were dominated by a pro-Christian bias and that they were needed to balance it," Mr Carlson said. "It has been violating the terms of that status ever since."

He interviewed Boyden Gray, a former counsel to President George HW Bush, who has filed a complaint with the IRS about Media Matters. "There is something wrong with the IRS," Mr Gray said. "There is nothing more harmful than to keep silent when you shouldn't be defending yourself."

The Daily Caller, which Mr Carlson founded in 2010, also repurposed a story it had written previously about some racist and transphobic slurs Mr Carusone used on a blog in 2005. Mr Carusone had spoken in a derogatory way about "trannies," "jewry," and "japs," in a series of posts.

He wrote about his boyfriend, now husband, saying that "despite his jewry, you KNOW he's adorable," in October 2005, for example.

Mr Carusone said the story, which he intended as satire, recirculates every time Media Matters is in the news. And he said the persona of the blog, which he wrote in college, was designed to parody a "right-wing blowhard."

"It didn't work very well and I killed it," he said. "It's not funny and it's not nice."

Ms Peltz said there is no doubt in her mind that Mr Carlson has been trying to "thread the needle of mainstreaming overt white nationalism," while also avoiding the consequences for it. She cited well-publicised instances: when Mr Carlson said immigration was making the country "dirtier," in December and another segment in which Mr Carlson claimed the South African government was seizing land from white owners, simply because they were white. Mr Carlson has defended that story.

Ms Peltz said she believes the extremism has been escalating.

"It's clear in the editorial choices that he makes that he covers demographic change as basically the end of white people," Ms Peltz said. "As someone with one of the largest platforms in media he frequently portrays himself as a victim. And that's a long tactic of white nationalists, going back all the way to the civil rights struggle in the South."

She said Mr Carlson's response to the audio's publication is a sign that it had an effect. Media Matters says they have more material; it is not clear if the releases will continue.

"There's a lot of stuff that I don't think Fox News is super proud of," Ms Peltz said. "It just took 10 hours a day [listening to] Bubba the Love Sponge to figure out."