Kristian Vikernes, nicknamed "Wolf" (or Varg in Norwegian) who is reportedly a sympathizer of Breivik was detained by anti-terrorist officers from France’s specialist DCRI unit on Tuesday morning at his farm in the rural Corrèze region in central France.
According to reports in the media, French intelligence services acted out of fears he could have been about to carry out a massacre, like the one committed by Breivik in Norway two years ago, when he killed 77 people in a bombing and mass shooting.
Later on Tuesday France's Interior Ministry said Vikernes was detained because he "could have been preparing carry out a major terrorist attack".
"He was a potential threat to society, as evidenced by the violence of his remarks, notably those intercepted on the internet," the ministry added in a statement.
The initial probe, opened a month ago by anti-terrorism authorities in Paris has labelled Vikernes — who investigators say wrote antisemitic and xenophobic messages online — as "dangerous", a police source told AFP.
Police acted after his French wife, the mother of his three children recently purchased four rifles. The wife has a license to own guns and is a member of a local shooting club but police feared the weapons had been bought for a far more sinister reason. The 25-year-old wife, named in French media as Marie Cachet, was also detained by police.
According to AFP officers seized several weapons at their home on Tuesday, including four 22 Caliber Long Rifles. Vikernes could be held in custody for the next 96 hours, as is allowed under French anti-terror laws.
Interior Minister Manuel Valls said authorities had decided it was important to arrest Vikernes "to act before and not afterwards."
"The DCRI (French domestic intelligence service) considered that messages he had posted on the Internet expressed huge violence," he said.
"The purchase of weapons and cartridges by his wife showed that a terrorist plan was possible. To know more, to know what this plan could be… the DCRI considered it was important to arrest and question him."
Vikernes – a convicted murderer
According to news website Le Point, Vikernes settled in France after serving part of a 21-year prison sentence in Norway for stabbing a friend in the 90s.
As a prominent part of Norway’s black metal scene at the time, Vikernes, who recorded music under the moniker ‘Burzum’, was also involved in burning down at least three Christian churches in the country.
Since moving to France, he has continued to write about the purported demise of European culture, attributing the decline to immigrant communities and supposed Jewish conspiracies.
In a blog entry published on Saturday, the neo-Nazi blamed a fatal train crash near Paris the previous day on “non-European scum” and made claims that “immigrant youths” had thrown stones at emergency services personnel, while robbing from victims of the crash.
He then claimed the fact that no media outlet in France had reported any incident of this type on a Jewish conspiracy between the French government and media.
In concluding, an angry Vikernes wrote: “I am so angry, and I have been the whole day, and I just don’t understand why Europe doesn’t revolt against this… It must stop; we must take actions to end this. Before it is too late.”
The neo-Nazi's links to Breivik are unclear other than the fact it is believed Breivik sent him a 1,500-page "manifesto" entitled 2083: A European Declaration of Independence, that was attributed to the terrorist and contained details of the preparation for his attacks.
However, in a post on his blog Vikernes heavily criticised Breivik for killing innocent Norwegians. Nevertheless French police were clearly concerned that there was a link between the two.
Breivik was sentenced to a minimum of 21 years in prison in August 2012 for the mass killings after court in Norway found him sane. His sentenced can be prolonged at a later date if he is still deemed a danger to society.
Breivik insisted the killings were necessary to stop the "Islamisation" of Norway.