It is a spring evening in Germany’s eastern city of Cottbus, and dozens of people have crowded into a small venue to hear a man who once dubbed himself the “friendly face” of National Socialism (Nazism).

Two other men with prior links to extremist groups are also in the room, including a candidate for forthcoming state elections.

They’re all there to hear Matthias Helferich at a youth event organised by members of the prominent far-right party, Alternative für Deutschland (AfD).

The AfD has repeatedly rejected accusations of extremism.

However, by investigating the past of these three men, the BBC has found a clear crossover between AfD figures and far-right networks, some of which are classed as anti-democratic or racist by German authorities.

Stephan Kramer, a regional spy chief in eastern Germany, has told the BBC the AfD now poses a danger to the “roots” of democracy, as the party eyes electoral gains in three states in the east this autumn: Saxony, Thuringia and Brandenburg.

Ahead of next month’s European elections the AfD, beset by extremism and corruption allegations, has dipped in the polls but still consistently places second nationwide.

It remains strong in Germany’s post-communist communities.

Matthias Helferich’s speech in Cottbus was all about “remigration” – a burgeoning concept within Europe’s far right about mass “returns” or deportations. The BBC asked to attend his talk but was told there wasn’t space.

Elected to Germany’s Bundestag in 2021, he was effectively barred from joining the AfD’s parliamentary faction, after damaging Facebook exchanges came to light dating back to 2016-17.

In leaked remarks Mr Helfrich mentions Nazism several times, including an apparent description of himself as the “friendly face” of National Socialism and as a “democratic Freisler” – a reference to Nazi-era judge, Roland Freisler.

Mr Helferich told the BBC he didn’t seriously call himself the friendly face of Nazism at all but was merely “parodying” left wingers online.

“If you are confronted with Nazi accusations as frequently as AfD politicians, you compensate for that in private spheres. You ridicule it.”

He continues to hold AfD roles at a local level and, as Cottbus shows, is welcomed within some party circles as an unapologetic proponent of “remigration”.

Many view the term as little more than a euphemism for the large-scale expulsion of people with migrant backgrounds, brought about by force or political pressure.

Matthias Helferich is outspoken about his hopes of “remigrating” millions in response to the “mass influx” of migrants from Africa and the Middle East.

But he claims that no-one who’s legally in Germany would be forced to leave – though some could be offered the chance to return to their “home country” and “culture.”

“This is not about downgrading people or deporting them for racist reasons. It is about preserving Germany as the land of the Germans,” he said.

Mr Helferich also spoke at a “summer party” last year hosted by the Institut für Staatspolitik (IfS), which months earlier had been designated as right-wing extremist by the federal domestic intelligence – which said the IfS was striving for an ethnically “homogeneous” nation.

“I don’t share the view of the intelligence service that it is a right-wing extremist organisation,” says Mr Helferich. “I decide for myself where I speak.”

AfD figures accuse domestic intelligence, the Verfassungsschutz, of being a body stuffed with government appointed officials, unfavourable to their cause.

More than “50 young patriots” came to hear the Cottbus speech, says one of its organisers, Jean-Pascal Hohm.

Mr Holm has held numerous roles in the AfD and is now running in September’s Brandenburg state elections. That is despite having been involved with – or linked to – a string of groups that went on to be classified as right-wing extremist.

They include the Ein Prozent (One Percent) association, Zukunft Heimat (Future Homeland) and Identitarian movement, which has been known to promote the “Great Replacement” conspiracy theory.

That’s the far-right idea that global elites are deliberately plotting to change the demographics of Western countries.

Mr Hohm is unapologetic in his belief that “population replacement” is going on in Germany and Europe – something he describes as “the main theme of our times”.

“I do not say that this is organised from up high, I say it is happening.”

In 2017, Jean-Pascal Hohm was spotted among the crowd when a group of football fans chanted antisemitic slogans. Some even gave what appeared to be the Hitler salute.

He insists he was “on the fringe” with his father: “This was a Cottbus away game, I am a Cottbuser.”

“It’s not my fault that some lunatics use this as a stage to do things which I expressly do not support,” he tells me.

Pictured smiling in the audience for Matthias Helferich’s talk in March was a man called Benedikt Kaiser, who works in parliament for Jürgen Pohl, an AfD MP in Thuringia.

An investigation by Die Welt newspaper found that Mr Kaiser moved in neo-Nazi circles between 2006-11, including being photographed at marches organised by the NPD – an ultranationalist party now known as Die Heimat (The Homeland).

A picture from social media, later deleted, also showed him as part of a far-right football hooligan group called the “New Society Boys”, since disbanded.

The name, abbreviated by the group as “NS”, is generally understood in Germany to mean “National Socialist”, or Nazi.

The photo was probably taken in or around 2009 and in it three men behind Benedikt Kaiser appear to be giving the Hitler salute.

Mr Kaiser did not respond to our requests for comment, however after this story was published he accused the BBC of using haphazard research by left-wing activists.

In a post on X he called for a “fundamental political turn… for our people, for our sovereignty – against the woke elites, against the abandonment of our social and cultural heritage”.

Years on, Benedikt Kaiser is now sometimes described as a thinker and theorist, winning lengthy praise from a figurehead of the AfD’s hard-right wing, Björn Höcke.

Mr Höcke is a history teacher turned charismatic leader of the AfD in Thuringia, meaning he’s running to be state governor.

A court has previously ruled it was not defamatory to express the opinion that Mr Höcke was a fascist.

The 52-year-old is currently on trial accused of knowingly using a Nazi slogan, though he has pleaded his innocence.

The blurred lines between party figures, within the AfD’s more radical faction, and “extremist” networks makes for a complex web of evolving groups and characters.

And it’s a party that is constantly dealing with divisions about whether to adopt a more moderate or radical message.

“Remigration”, for example, is an idea being embraced by some figures and kept at arm’s length by others.

The concept is championed by Austrian activist Martin Sellner, who has a neo-Nazi past, and has been banned from both Germany and the UK.

He has written about “remigrating” asylum seekers, “foreigners” with residency rights and “non-assimilated” citizens.

Reports that senior AfD figures were involved in a “secret” meeting about remigration with Martin Sellner outside Berlin sparked mass demonstrations in Germany earlier this year.

The AfD is a movement that has, in the past decade, moved “more and more from a conservative, democratic party towards a right-wing extremist party,” believes Stephan Kramer, the President of the Office for the Protection of the Constitution in Thuringia.

An outspoken civil servant, and a member of Chancellor Olaf Scholz’s Social Democratic Party (SPD), Mr Kramer says the AfD’s chances of winning the most seats in his own state this autumn are “very, very good”.

Previously the general secretary of the Central Council of Jews in Germany, he says he would leave the country if the AfD won power.

The party’s “nationalistic” views risk “turning Germany back into something that we’ve probably only seen between 1933 and 1945”, he told the BBC.

AfD figures have argued that they are being targeted by state authorities that are biased against them, but Mr Kramer is adamant that is not the case: “We’re not politicised because we’re working on the basis of German law and any decision that is taken… can be challenged in front of a court.”

A legal challenge by the AfD is ongoing – against its designation as “suspected” right-wing extremist, while its youth wing is classed as a confirmed case.

Stephan Kramer sees the party as the “parliamentarian arm” of the new right that’s building momentum across Europe – and even claims it poses a risk to democracy.

“When I’m speaking about a German oak – [a] big strong old tree, it can take a blizzard, it can take a storm.”

“But once you have an enemy that goes for the roots – and that’s exactly what’s happening right now… it’s very dangerous because it goes to the vital parts of our democracy.”

More broadly, Stephan Kramer fears that the political temperature in Germany is “heating up”.

On Friday, a lead SPD candidate in next month’s European elections, Matthias Ecke, needed surgery after being attacked as he hung up posters in Saxony.

Four teenagers, aged 17-18, are being investigated with police saying there is reason to believe that at least one of the suspects has extreme right-wing views.

AfD supporters we have spoken to insist their movement is not extreme at all and even represents the centre-ground.

This story is not just about three men at a talk in Cottbus, but about a divide in Germany over what counts as extremism and fears of a return to its ugly past.

Additional research by Nicholas Potter.