OSLO, Norway (AP) -- The Norwegian man who admitted killing 76 people in a bombing and youth camp massacre is a sociopath who acted without accomplices or a network of like-minded right-wing extremists, and kept his plans to himself for more than a decade, a top security official said Thursday.

"It's a unique case. It's unique person. He is total evil," Janne Kristiansen, the director of the Norwegian Police Security Service told The Associated Press.

Anders Behring Breivik claims he carried out the July 22 attacks as part of a network of modern-day crusaders plotting a revolution against a multicultural Europe, and that there are other cells ready to strike.

But investigators have found no signs - before or after the attacks - of a larger conspiracy, though it's too early to rule it out completely, Kristiansen said.

"On the information we have so far, and I emphasize so far, we have no indication that he was part of a network or had any accomplices, or that there are other cells," Kristiansen told AP.

She said Breivik doesn't appear to have shared his plot with anyone, and lived an outwardly lawful and moderate life before carrying out the attacks with "total precision."

Breivik has admitted that he set off a car bomb in the government district of Oslo, killing at least eight people, then drove several miles (kilometers) northwest of the Norwegian capital to an island where the youth wing of the ruling Labor Party was holding its annual summer camp. He arrived at Utoya island posing as a police officer, then opened fire on scores of unsuspecting youth, executing them one after the other as they tried to flee into the water. Sixty-eight people died, many of them teenagers.

Kristiansen said that Breivik's case presents a new challenge for security services, different from a "solo terrorist" who receives training and instructions from a terror network and is then left to pick out a target and attack it on his own. Breivik appears to be a true lone actor, who conceived and executed his plot without help or coordination from anyone.

"This is a totally different challenge," Kristiansen said. "This is all in his mind."

Judging by a manifesto he released just before the attacks, he started "preparing himself to do something big, shocking and spectacular" some 10-12 years ago, she said. The 1,500-document calls for a revolution that will culminate by 2083 in the expulsion of Muslims from Europe and the elimination of the "cultural Marxist/multiculturalist" politics that Breivik complains facilitated the immigration of Muslims to European countries.

At his arraignment on Monday, he took responsibility for both attacks but pleaded not guilty because he thinks he's in state of war, his defense lawyer Geir Lippestad said.

Invstigators will interview Anders Behring Breivik again on Friday and will focus on whether there is "any more danger," police attorney Paal-Fredrick Hjort Kraby told reporters.

Police have not turned up any signs that copycat attacks ight be committed, Kraby said.

But they are clearly concerned that Breivik could inspire others. Kraby said Brevik's next hearing will be closed "just in case he's able to send messages by code" to associates.

Police are on high alert for copycats across Europe: Finnish police said they had arrested an 18-year-old man who ordered 22 pounds (10 kilograms) of fertilizer from Poland to build make explosives. Police said the case appeared to have no connections to the massacre; the national broadcaster YLE cited police as saying the man told them he wanted to make fireworks.

Police have so far only interviewed the Norwegian suspect once, in a seven-hour session the day after the attack. Kraby said Breivik is in contact only with his lawyer and investigators. He also said the Norwegian police have been in touch with the FBI regarding the attacks, but he did not elaborate.

Breivik's attorney has said his client considers himself a "savior" and that he is likely insane. Breivik has pleaded not guilty to the terrorism charges he faces.

The attacker was wearing a home-made police uniform during the slaughter at the island youth camp and urged victims to come closer to him before shooting. Kraby said the uniform included a police emblem on the shirt, but it was not clear where he had obtained it.

The search for missing has ended on the island but is still ongoing in the water surrounding it, police said.

Norway's response to the attack on a Labor Party youth camp on the island of Utoya, has been criticized. Though it is just 25 miles (40 kilometers) from Oslo, police didn't get there until 90 minutes after the shooting started. They had no helicopter available, and the first boat that police tried to take to the island broke down.

The leader of Norway's Delta Force anti-terror police unit on Wednesday defended the special operations team and said the breakdown didn't cause a significant delay. The team jumped into other boats and got to Utoya quickly, police officials said.

Police gave an eerie account of the end of the siege, saying Breivik obediently gave up the moment police approached him, holding his hands over his head.

"It was a completely normal arrest," said officer Haavard Gaasbakk.

Prime Minister Jens Stoltenberg said Wednesday an independent commission will be formed to investigate the attacks and determine what lessons can be learned from the response. The commission also is to help survivors and relatives cope with the aftermath. Parliament said it is willing to help pay for funerals, and a monument will be built to commemorate the victims.

He said Norway will never be the same, but insisted the massacre shouldn't change the country's culture of tolerance, calling on Norwegians to embrace the openness Breivik said he was trying to destroy.

Perhaps mindful of many Norwegians' reserved ways, Stoltenberg urged the country to fully grieve: "I have cried, and I have told many people that they should not hesitate to cry."

The national sense of heartbreak is being renewed daily as police slowly release names of the dead. The identities of only 17 of those known to have been killed have been officially confirmed. Eight died in the explosion and 68 died in the camp shootings.

Georgian officials said Thursday the body of a young Georgian woman missing after the shooting rampage has been found. Tamta Liparteliani's body had been found on the bottom of the lake with gunshot wounds in the back. She was identified by her fingerprints, Georgian Deputy Foreign Minister Nino Kalandadze said.

The youngest known victim so far was identified Wednesday - camper Sharidyn Svebakk-Bohn, who turned 14 five days before the rampage. Another victim confirmed dead at the camp was a stepbrother of Crown Princess Mette-Marit, 51-year-old police officer Trond Berntsen, who had been providing security on the island.

An employee of Stoltenberg's office, 51-year-old Anne Lise Holter, was confirmed Wednesday as one of the eight dead in the bomb blast.

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Heintz reported from Stockholm. Louise Nordstrom in Stockholm and Bjoern H. Amland in Oslo contributed to this report.

(This version corrects that Finnish suspect told police he wanted to make fireworks, corrects time that police arrived at island youth camp.)

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