Norwegian police said they will question Anders Behring Breivik again on Friday as new information emerged about his killing spree and prosecutors said he would not go on trial before 2012.
This will be the second time that police interrogate the far-right extremist since Saturday, the morning after his shooting rampage on Utoeya island and the bomb blast in downtown Oslo that killed 76 people altogether.
Police official Paal-Fredrik Hjort Kraby said officers will question Behring Breivik on "information received over the last few days -- which is a lot," although he did not elaborate.
European counter-terrorism experts met in Brussels to look at lessons that can be drawn from the attacks, and an Oslo gun club said Behring Breivik had been a member since 2005.
But as the depth and complexity of the investigation spread, the country's highest legal officer said it would take time to sift through the evidence.
"We hope that we can conduct the court trial in the course of next year," the Norwegian king's prosecutor general Tor Aksel Buschhe said, adding that Behring Breivik's indictment "will not be ready before the end of the year".
The possibility that Behring Breivik had been working with other people was receding, officials said, despite an international intelligence probe.
The possibility "has become weaker over time," police spokesman Henning Holtaas told AFP, although "we are checking all his communications".
He would not confirm that Behring Breivik was carrying a walkie-talkie radio on Utoeya island, where he shot dead 68 mostly young people, but two witnesses have said he was.
Behring Breivik boasted before the attack in a 1,500-page manifesto that he was one of up to 80 "solo martyr cells" recruited across Western Europe to topple governments tolerant of Islam.
Norway's intelligence service has been liaising with counterparts in Europe and the United States but has found nothing to verify the gunman's claims of active cells forming a terror "organisation".
A British man cited by Behring Breivik as his "mentor" on Friday denounced the Norwegian's actions as "pure evil" and "did not equate to anything I am involved in".
Speaking to The Times newspaper, Paul Ray admitted he may have been the inspiration behind Behring Breivik's massacre, but said he had rejected the attacker's Facebook friend request because he "didn't like the look of him".
Ray, 35, is the leader of a Knights Templar movement inspired by the actions of mediaval crusaders against Islam and runs a "Richard the Lionhearted" blog that is believed to have underpinned Behring Breivik's online manifesto.
"I am being implicated as his mentor," said Ray, who left Britain for Malta in 2008 after he was arrested for allegedly inciting racial hatred on his blog.
"I definitely could have been his inspiration," he conceded. "He has given me a platform and a profile but what he did was pure evil. I could never use what he has done to further my own beliefs."
Norway's intelligence services chief Janne Kristiansen told AFP the possibility the killer had acted as a "lone wolf" could make it more difficult for police to uncover his trail.
European Union terrorism experts meeting in Brussels warned that the bloodbath in Norway, which they said was almost "impossible to prevent", underlined the need for stronger European counter-terrorism action.
Police are still searching the waters around Utoeya and the bombing site in downtown Oslo for missing persons, although they said Thursday that the land search on the island had ended.
Police on Thursday released the identities of 24 more people, aged between 14 and 30. One of them was among the eight people killed in the initial car bomb blast in central Oslo, while the others died on Utoeya island.
The list included one Georgian, and brought the total number of confirmed dead whose names have been made public to 41.
The gunman's 76-year-old father Jens Breivik, who lives in the south of France, said in an interview published Friday that he "does not want to talk any more about my son... a terrorist".
He told the daily La Depeche du Midi in what he said was his "last interview" that "I have nothing to do with this terrorist".
Survivor Emma Martinovic, 18, recounted in a blog that: "I heard the bastard laugh, I heard him shout 'you won't get away'."
Testimonials started emerging Thursday of a lost generation of future Norwegian political leaders brutally cut down.
These included Anders Kristiansen, an 18-year-old whose mother said he "dreamed of becoming prime minister since the age of five" and whose shining talent was lauded by Norwegian Foreign Minister Jonas Gahr Stoere in the national press.