In the minutely detailed diary he began compiling May 1, Anders Behring Breivik comes across as obsessive, anxious and narcissistic. Meticulously recording his actions, he describes how he assembled the explosives he would use to set off a car bomb in Oslo and how he prepared for the shooting spree he would then launch on the island of Utoya.

For 82 days, he wrote it all down.

Is his account accurate? In places, almost certainly not. But overall, it provides a largely plausible picture of the mundane details Breivik attended to as he readied for mass murder.

A shocked and grieving nation remained fixated on the news Sunday. The royal family attended an emotional memorial service at the national cathedral.

“Every one of those gone is a tragedy,” Prime Minister Jens Stoltenberg told the congregation. “Together it counts as a national disaster.”

As sobs erupted in the church, Stoltenberg appeared to be close to crying as he spoke of friends who were killed at Utoya. On Sunday night, a sea of flowers, candles and small Norwegian flags covered the plaza outside the cathedral, while a silent crowd kept watch.

Breivik, a 32-year-old who contends he is waging a Christian crusade against multiculturalism in Europe, believes the killings were “gruesome” but “necessary,” said his attorney, Geir Lippestad. Breivik has acknowledged that he carried out the attacks, his attorney said, but he denies criminal responsibility. Police officials said Sunday that Breivik told them he acted without an accomplice.

His diary is part of a 1,500-page manifesto that Breivik admits posting on the Internet, Lippestad says. Part history, part commentary, part how-to manual, it lays out his loathing of Islam and his determination to preserve a Christian Europe. It is written in English, a language Scandinavians often turn to when trying to reach the broadest possible audience. The Norwegian newspaper VG has reported that sections of it were lifted from the manifesto of Ted Kaczynski, the Unabomber.

As of Sunday evening, Breivik’s one-man revolution had left 93 dead and 96 injured, with four still missing. Divers continued to search the waters around the island for bodies.

A judge ruled Monday that Breivik will be held in isolation for four weeks because he might tamper with evidence and claims there are “two more cells in our organization,” the Associated Press reported. Although he has acknowledged the bombing and shooting, he pleaded not guilty and told the court was trying to save Europe from Islam, news services said.

Careful planning

Breivik writes in his manifesto about the period before he began his diary. He says that he had been preparing for the attacks for years — and that he was determined to err on the side of killing too many people rather than too few.

In April, he began his preparations in earnest. He rented a farm in the village of Aasta, in the Hedmark region of Norway, from a man who was going to prison for growing marijuana. His stated intention was to grow sugar beets, because he had learned that they require a large amount of fertilizer — which he planned to use to make bombs.

Even before he moved out of his mother’s Oslo apartment, he had ordered six tons of fertilizer. It was delivered to the farm May 4, the dealer who sold it to him told the Bergens Tidende newspaper.

By that time, Breivik had rented, from Avis, the first of two vehicles that he apparently used in the attacks. This one was a silver-gray Fiat Doblo van that, according to the manufacturer, had 1,500 pounds of carrying capacity.

As the diary begins May 1, the task Breivik sets for himself is to mix the ingredients for the explosives in the privacy of the farm, a drive of several hours from Oslo — and almost next door to Norway’s newest military base. There are close calls when neighbors drop by, and he writes in detail about mistakes he makes.

Along the way he complains about Norway’s entry in the Eurovision Song Contest — “an asylum seeker from Kenya” — and about the shoddy Chinese equipment he is using.

On June 11, he writes, “I prayed for the first time in a very long time today.” He asked God to “ensure that I succeed with my mission.”

On June 25, he goes into town for some Chinese takeout and notices “a relatively hot girl” checking him out. Here is a moment to reinforce his self-regard. “Refined individuals like myself is a rare commodity here,” he writes — one of the few times his English grammar fails him.

Breivik owned a Glock semi-automatic pistol and a .223 Ruger Mini-14 rifle. Initially, he writes, he bought hollow-point bullets, but he replaced them in early July with soft-point bullets — more suitable, he writes, for “inflicting maximum damage to vermin.”

On July 15, he is nearly ready to move, and he is just about out of money. (He had calculated his net worth in early March at about $18,000.) But he has enough to rent a Volkswagen Crafter van with a capacity of nearly 1.5 tons.

At this point, his narrative starts to become difficult to follow — perhaps deliberately so, though he writes that he is taking body-building supplements and hints that he is also on amphetamines. There’s a mention of a trip to the far north to test a batch of explosives, as well as many passages about moving the vans around, written in what’s almost code. In his last entry, Breivik writes about extracting gold from the dirt with the explosives, so he can pay back his investors.

On July 20, he uploads to the Web a 12-minute video he made in February that encapsulates his obsession with race and religion.

“Multiculturalism,” he says, “is an anti-European hate ideology designed to deconstruct European cultures and traditions, European identities, European Christendom and even European nation-states. And, as such, it is an evil genocidal ideology created for the sole purpose of annihilating everything European.”

It ends with photos of him in quasi-military dress. “Onward, Christian soldiers!” he says. “Celebrate us, the martyrs of the conservative revolution, for we will soon dine in the Kingdom of Heaven.”

Police stranded onshore

By Friday, he had taken two vehicles to Oslo, apparently riding the train back to the farm. One — presumably the larger of the vans — he parked on a street called Grubbegatta, amid buildings housing government ministries. (A police spokesman said Sunday that he was unable to release information about either of the vehicles Breivik used.) Norwegian newspapers have quoted experts who calculate that the one on Grubbegatta may have been carrying a little more than 1,000 pounds of explosives.

At 3:26 p.m., it detonated. Seven people were killed, 30 were injured, windows were smashed blocks away, and the entire neighborhood was evacuated. More people might have been hurt, except that on a summer Friday afternoon many were gone for the weekend. Police officials, concerned there might be more bombs, flooded the center of the city with teams of officers.

Sometime afterward, Breivik drove into Hoenefoss, the mainland town opposite Utoya, about an hour from Oslo. He was wearing a police uniform. He got on the passenger ferry to the island; because of the explosion in Oslo, it was making its last run of the day at 5 p.m.

He said he had to gather the teenagers who were attending a Labor Party camp there to brief them on the bombing in the city. He had two weapons with him, and within minutes he opened fire.

Anders Nohre Berg, a dentist, said he and other residents on the mainland heard the shots. At 5:27 p.m., one of them called police in nearby Buskerud. Three minutes later, someone called police in Oslo. At 5:38, Buskerud police asked Oslo for help, according to police records.

As Breivik stalked the relatively small island, people on the mainland shore saw campers diving into the water. Some set out in boats to rescue them. One boat made it to a cove on the island to haul young people away, according to published accounts. One resident said she thought as many as 250 people had been rescued.

As the minutes ticked by, gunshots continued to ring out. At 5:52 p.m., the first police patrol arrived at a spot on the mainland opposite the island, according to a police account. At 6:09, an emergency squad from Oslo arrived. The squad had had to drive because no helicopter was on standby, Police Chief Sveinung Sponheim said at a news conference Saturday.

But there was no boat. In a country with a proud seafaring tradition, the elite police unit was stranded onshore. Finally, Berg and others took the SWAT team to the island in their own motorboats. They landed at 6:25, well over an hour after the shooting began. Breivik was arrested without incident two minutes later. Police officers fired no shots.

He had apparently made no getaway plans, nor did he choose to give up his own life in the cause of his crusade.

Correspondent Michael Birnbaum in Berlin and staff writer Alice Fordham in Washington contributed to this report.