Mass murderer Anders Behring Breivik faces a judge – and explains why he killed 76 people

Police investigate suggestion that accomplices were involved / Killer was on Norwegian intelligence service's watch list

Kept from the public's gaze at a closed Norwegian court hearing yesterday, the man who killed scores of people in two terror attacks nonetheless retained the world's attention as the authorities said that they were investigating his claims to have worked alongside "two more" terror cells.

Anders Behring Breivik's astonishing claim came as a Norwegian court ruled that the self-confessed mass murderer should be held in prison for the next eight weeks, four of which will be in total isolation, without visits and letters or access to the internet and newspapers.

Amid growing anger within Norway that the 32-year-old man responsible for so many deaths would try to use his court appearance as a propaganda coup, a strategy outlined in the 1,500-page manifesto that Breivik published just hours before the slaughter began, Judge Kim Heger also conducted the hearing behind closed doors. The court cited fears of a security risk posed by a public hearing.

Oslo's police force is investigating whether the perpetrator of Norway's worst violence since the Second World War had help from ideological or practical accomplices. Police last night said Breivik's testimony to them had been inconsistent – telling investigators that he acted alone and also that he had help from "two more cells".

In his manifesto Breivik claims to have founded an anti-Muslim "Knights Templar" in London eight years ago. The group's existence is currently being investigated by security officials across Europe who have said they are aware of increased internet chatter from individuals claiming they belong to the same organisation.

"We cannot completely, and I stress completely, rule out that others were involved in what happened," police attorney Christian Hatlo told a news conference when asked about the other cells.

Mr Hatlo added that Breivik "seemed unaffected by what had happened" but was prepared to spend the rest of his life in prison. He had admitted to carrying out the attacks but has refused to plead guilty.

It also emerged last night that the PST, Norway's equivalent of the MI5, had Breivik's name on an April watch list of 60 people who had purchased chemicals from a retailer in Poland. But it was considered a legitimate transaction and too small an amount to warrant further investigation. It is now thought some of the chemicals bought from Poland were used to make his car bomb.

Police last night reduced the final death toll from the Utoya shootings from 86 people to 68, citing the difficult conditions and confusion following the killings for the higher figure earlier in the week. The total number of victims killed in both attacks is now 76 after an eighth person died from the Oslo bomb blast. More than 90 have been injured, many critically with gunshot wounds from dum-dum bullets that shattered on impact. Tens of thousands of people across Norway turned out for a vigil last night in memory of those who died.

The gatherings were the culmination of a dramatic day which started when angry crowds gathered outside Oslo District Court as Breivik was driven in through an underground side entrance in a convoy of armoured Mercedes jeeps for his first court appearance since his arrest.

Dressed in a red jumper, he smiled to waiting spectators as he was driven away after a 35-minute hearing. Some of those watching were heard to shout: "You are a traitor to your country."

To the horror of many Norwegians, Breivik had already told his defence lawyer that he was going to use his first appearance in Court 828 to explain why he carried out Friday's attacks and wanted to wear a uniform as he did so. The request was refused and he was halted by court officials from reading extracts of his manifesto.

Instead it was left up to Judge Heger to convey Breivik's raison d'être after he ordered media out of the court, citing the ongoing police investigation and security concerns. Breivik's motivation, the judge said, was to "save" Europe from Islam and punish Norway's current Labour coalition government for its welcoming approach to refugees.

"The operation was not to kill as many people as possible," the judge said. "[It was] to give a strong signal that could not be misunderstood that as long as the Labour Party keeps driving its ideological lie and keeps deconstructing Norwegian culture and mass-importing Muslims, then they must assume responsibility for this treason."

After accepting a request from prosecutors, the judge ruled that Breivik would be held for four weeks in total isolation without any access to the outside world, and then for a further four weeks after that. Only his lawyer will be allowed to visit him. Prosecutors are able to keep renewing his incarceration until trial. The maximum custodial sentence for a crime in Norway is 21 years, a figure that is testament to the country's sincere belief in rehabilitative punishment.

However, if prison authorities believe someone still poses a threat to society they can extend the prison sentence every five years. Two psychiatrists have now been commissioned to assess Breivik's mental health. If he is declared insane he can be held indefinitely.

In a country renowned for its transparency, however, it is highly unusual for a provisional court hearing to be heard in private. But among the crowds outside the courthouse there was widespread support for the judge's decision.

"I'm very angry, very upset and I don't want to hear any more from him," said Bengt Fors, a theatre worker who had gathered with her friends on the court steps. "We know he has a propaganda plan and I don't think we should give him what he wants."