OSLO -- Amid an outpouring of grief and solidarity, police in Norway are widening their investigation following a claim by the sole killer in Friday's killings that he had worked with collaborators.

The defense lawyer for Anders Behring Breivik said Tuesday the terrorist says he is part of an organization with several cells in Western countries and his attacks in Norway were necessary because he's in a state of war, AP reported.
Geir Lippestad told reporters that Breivik talked about “two cells in Norway but several cells abroad.”
People gathered in the capital, Oslo, on Tuesday to pay homage to the victims of the twin attacks that left 76 people dead.
Breivik, a 32-year-old Norwegian man, is accused of carrying out the bombing in Oslo and the shooting spree on the resort island of Utoeya.
“The whole street is completely filled with flowers and candles.” Al Jazeera's Harry Smith reported from Oslo.
Up to 150,000 people paid homage in Oslo on Monday evening: mourners sang songs and cheered in solidarity while others placed flowers on a memorial wall next to the city hall.
Jens Stoltenberg, the prime minister, told the crowds in Oslo that Norway would not be defeated by the tragedy.
“Evil can kill a person, but it can never defeat a whole nation,” he said, to loud applause.
“With the strongest of all the world's weapons - freedom of speech and democracy - do we set the course for Norway post 22 July 2011,” Stoltenberg said.
The original aim had been to hold a memorial procession for those who lost their lives in the bombing and shooting, but the numbers of people were so great that the crowds simply held a mass gathering.
'Two further cells'
Earlier, at Monday's court hearing in Oslo, Breivik said on being remanded in custody that he had “two further cells” in his organization.
A senior court official declined to elaborate on Breivik's claim after the hearing. Instead, Geir Engebretsen, the court's chief, repeated the ruling of Judge Kim Heger who is trying Breivik's case.
Earlier Heger said: “The accused has made statements today that require further investigation, including that 'there are two more cells in our organization'.”
Breivik had previously said he acted alone in the attacks. Breivik also calmly said in court that that he expects to spend the rest of his life in prison, officials said.
The judge ordered eight weeks' detention for Breivik, who has admitted to the attacks. Breivik told the court that he acted to save Europe from Islam.
Heger said that Breivik would be locked up alone with no incoming letters, media nor visitors except for his lawyer. A trial could be a year away.
'Perception of reality'
Breivik had requested his hearing be open to the public in order to “explain fully what he's done, and more importantly, why he did it”, Al Jazeera's Harry Smith reported from Oslo.
Geir Lippestad, Breivik's lawyer, told NRK television his client had expected to be shot dead by angry Norwegians on his way to court.
But after requests from prosecutors and police to close the arraignment, the judge barred the media and public from attending.
“He has a completely different perception of reality than us other Norwegians, for instance he thinks that torture exists in prisons in Norway,” Lippestad said.