On the second day of an appeals case into Breivik's prison conditions, Attorney General Fredrik Sejersted told the court the right-wing extremist, who killed 77 people in twin attacks in 2011, was following the script outlined in his 1,500-page anti-immigration manifesto he published just before his killing spree.
"He has completed the active phase, and now he is working on his project as an ideologist and a writer to create networks," Sejersted said. "There is unfortunately reason to believe that Breivik's ideological project is unfolding as planned."
The 37-year-old Breivik noted in a letter that he has considered the possibility of using "national-socialist dating adverts" as a means of spreading his ideology, since their content is protected under the European Court of Human Rights. Like all of his correspondence it was read out by prison officials.
"Basically, I consider the writing of dating adverts such a lame activity that it should be criminalised," Breivik wrote in a letter to supporters in August 2015 and from which Sejersted read excerpts to the court.
"But in a bid to break the blockade on information at almost any price, I envisage an experiment. Paradoxically, there is no other type of text that is as protected as the publication of a dating advert," Breivik wrote.
In an advert penned as an example in the letter, Breivik insists that the object of his affections must "facilitate the publication" of one of his texts.
The appeals court is examining Breivik's case after a lower court in Oslo ruled in April that his rights had been violated and he was subjected to "inhumane" and "degrading" treatment in prison, largely because he has been isolated from other inmates for five-and-a-half years.
For security reasons, the appeals case is being heard in the gymnasium of the Skien prison where Breivik is incarcerated.
In July 2011, Breivik tracked and gunned down 69 people, most of them teenagers, at a Labour Party youth camp on the island of Utoya, shortly after he killed eight people in a bombing outside a government building in Oslo.
He said he killed his victims because they valued multiculturalism.
He was sentenced in 2012 to 21 years in prison, which can be extended indefinitely as long as he is considered a threat.
- Still considered dangerous -
In his preliminary remarks, Sejersted has argued that the strict prison conditions imposed on Breivik are justified by the danger he poses and the need to prevent him from building a network capable of carrying out new attacks.
"There would have to be long lasting, dramatic changes for him to be considered as no longer dangerous," psychiatrist Randi Rosenquist said in a report in December, cited by Sejersted.
"The fact that he conducts himself in exemplary fashion in prison provides no guarantee," she added.
Sejerstad said he was in "extraordinary physical and psychological form," and denied that Breivik was isolated.
The state argues he has multiple contacts with guards, with whom he plays backgammon, and meets his lawyers and priests.
But Breivik's lawyer Oystein Storrvik said he was "mentally vulnerable" adding: "there is no person of confidence with whom he can speak and with whom he can build up a relationship."
Storrvik said the only person to have visited him was his mother, who was once able to hold him briefly before she died.
On Wednesday, Breivik refrained from repeating the raised-arm Nazi salute that he made at Tuesday's opening of the hearing, and which earned him a reprimand from the judge.
Breivik is scheduled to testify on Thursday, and the hearing is expected to wrap up on January 18.
While Norway attempts to turn the page on this traumatic episode in its history, survivors and victims' families have largely remained silent and stayed away from the media frenzy surrounding Breivik, of which they are highly critical.