Restrained by a police leash, the Norwegian man who confessed to killing 69 people at an island youth camp reconstructed his actions for police in a trip back to the crime scene.
Anders Behring Breivik, 32, described the killings in close detail during an eight-hour tour on the island with up to a dozen police, prosecutor Paal-Fredrik Hjort Kraby told a press conference in Oslo, ABC reported
He reportedly showed no remorse, police said.
"He was not unaffected, but he showed no remorse for his actions," police prosecutor Paal-Fredrik Hjort Kraby told reporters in Oslo.
Hjort Kraby said Saturday's site visit had been important to the case, the AFP reported.
"All research shows that it helps the memory to come back to the scene of the crime. (Behring Breivik) provided us with a lot of new information which we didn't have before, despite 50 hours of (previous) interrogation," the police prosecutor said.
"We feel we have a fairly good overview of how everyone died or was shot now, even though there are still details to fill in," he said, adding some of the victims had died had drowned trying to swim for safety, the AFP reported.
Behring Breivik was taken to the island some 40 km from Oslo, first by car and then by the same boat he used on the day of the attacks.
"He remembered new things," Kraby said, adding there were no major inconsistencies in his account although "sometimes he would walk in the wrong direction and then correct himself."
The police prosecutor confirmed weekend news reports that authorities had Breivik x-rayed a few days after his arrest on Utoeya for fear he may have swallowed an explosive device or remote control.
Behring Breivik has said that targeting Prime Minister Jens Stoltenberg's Labour Party was part of a "crusade" to halt a "Muslim invasion" and multiculturalism in Europe.