The man blamed for attacks on Norway's government headquarters and an island retreat for young people that left at least 93 dead said he was motivated by a desire to bring about a revolution in Norwegian society, his lawyer said Sunday.

A manifesto he published online — which police are poring over and said was posted the day of the attack — ranted against Muslim immigration to Europe and vowed revenge on “indigenous Europeans,” whom he accused of betraying their heritage. It added that they would be punished for their “treasonous acts.”

The lawyer for the 32-year-old Norwegian suspect, Anders Behring Breivik, said Sunday that his client wrote the document alone.

While police said they were investigating reports of a second assailant on the island, the lawyer said Breivik claims also claims no one helped him.

The treatise detailed plans to acquire firearms and explosives, and even appeared to describe a test explosion- “BOOM! The detonation was successful!!!” It ends with a note dated 12.51 p.m. on July 22 — “I believe this will be my last entry.”

That day, a bomb killed seven people in downtown Oslo and, hours later, a gunman opened fire on dozens of young people at a retreat on Utoya island.

Police said on Sunday that the death toll in the shooting rose to 86.

That brings the number of victims to 93, with more than 90 wounded.

There are still people missing at both scenes. Six hearses pulled up at the shore of the lake surrounding the island on Sunday, as rescuers on boats continued to search for bodies in the water. Body parts remain inside the Oslo building, which housed the prime minister's office.

Police and his lawyer have said that Mr. Breivik confessed to the twin attacks, but denied criminal responsibility for a day that shook peaceful Norway to its core and was the deadliest ever in peacetime.

Mr. Breivik has been charged with terrorism and will be arraigned on Monday.

Geir Lippestad, Mr. Breivik's lawyer, said his client has asked for an open court hearing “because he wants to explain himself.”

Police Chief Sveinung Sponheim said a forensics expert from Interpol would join the investigation on Sunday.

European security officials said on Sunday they were aware of increased Internet chatter from individuals claiming they belonged to the Knights Templar group that Mr. Breivik refers to in the manifesto.

They said they were still investigating claims that Mr. Breivik, and other far-right individuals, attended a London meeting of the group in 2002.

The officials would also not immediately confirm that they had been aware of Mr. Breivik as a potential threat.

Mourning

As authorities pursued the suspect's motives, Oslo mourned the victims. Norway's King Harald V and his wife Queen Sonja and Prime Minister Jens Stoltenberg crowded into Oslo Cathedral, where the pews were packed, and people spilled into the plaza outside the building. The area was strewn with flowers and candles, and people who could not fit in the grand church huddled under umbrellas in a drizzle.

The king and queen both wiped tears from their eyes during the service for “sorrow and hope.”

Afterward, people sobbed and hugged one another in the streets, as many lingered over the memorial of flowers and candles. The royal couple and prime minister later visited the site of the bombing in Oslo.

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