"We feel sure of this conclusion: no evidence in this case suggests any physical or psychological accomplices," Oslo police chief Kenneth Wilberg told the Oslo district court on the 27th day of the right-wing extremist's trial.

Breivik has insisted to police and in the 1,500-page ideological manifesto he posted online shortly before carrying out his twin attacks on July 22nd that he was part of a pan-European organization, the Knights Templar, established in London in 2002 to protect Europe from multiculturalism and a pending "Muslim invasion".

In court, the 33-year-old confessed killer acknowledged that his description of the organization and his role in it had been "pompous" or exaggerated, saying the group had just six members but continuing to insist that the other "cells" could strike at any moment.

"Police have not found evidence that the Knights Templar exists in the shape suggested by the accused," Wilberg said, presenting the results of the biggest investigation in Norwegian history with at times up to 1,000 police officers working on the case.

He acknowledged that police had not managed to identify most of the 8,000 people Breivik had wanted to send his manifesto to on July 22nd.

The extremist has insisted that another member of the Knights Templar is on that list.

Finding that person would be like "searching for a needle among 8,000 other needles," Wilberg said.

On the day of his massacre, Breivik managed to email his manifesto to around 1,000 of the some 8,000 people he had meant to send it to, due to a network provider spam filter limiting the number of recipients.

"We have documented large parts of Breivik's life, but we have not identified any accomplices," Alf Nissen of the Norwegian criminal police told the court.

"But in theory, it is impossible to prove that something does not exist. All we can do is to look, look, look, and, at some point, we have to conclude that this doesn't exist," he added.

As the 10-week trial continues, some 50 police officers are still involved in investigating the July 22nd attacks.

On that day, Breivik, who has been charged with committing acts of terror, first bombed a government building in Oslo, killing eight people, before going on a shooting rampage on the nearby Utøya island, where the ruling Labour Party's youth wing was hosting a summer camp.

Sixty-nine people perished in the island massacre, most of them teens.