Norwegian police freed several people who were briefly detained Sunday after a raid prompted by attacks that have killed 93 people, a police lawyer told Reuters.
"The people detained and brought in for questioning have been released. They were in no way linked to the case," Anders Frydenberg said. Police are trying to see if the main suspect acted alone.
Frydenberg said that no explosives were found in the raid on buildings in north east Oslo.
Police have previously said that they were likely to stage follow-up actions as they try to confirm that there are no additional threats.
Anders Behring Breivik, the 32-year-old man suspected of the shooting and bomb massacre, earlier called his deeds "atrocious" yet "necessary," his lawyer said Sunday.
Meanwhile, a 1,500-page manifesto emerged that carried detailed planning for and direct references to an attack on the summer camp where most of the deaths occurred.
Breivik is suspected of killing at least 86 people — mostly teens — on a tiny forested holiday island that was hosting a summer camp for the youth wing of Norway's ruling Labor party. Breivik was also charged in the bombing of Oslo's government district, which killed seven people hours earlier.
"He has said that he believed the actions were atrocious, but that in his head they were necessary," defense lawyer Geir Lippestad told TV2 news.
Lippestad said his client was willing to explain himself in a court hearing on Monday. The court will decide at the hearing whether to keep the suspect in detention pending his trial.
If convicted on the terrorism charges, he would face a maximum of 21 years in jail, police said.
It was unclear what unleashed the bloodshed, though news agency NTB said Breivik was a member of a gun club and legally owned firearms. At the shooting, police said Breivik carried a Glock pistol and an automatic weapon. Police said Breivik surrendered to authorities and has since confessed.