The far-right activist suspected of carrying out Friday’s terror attacks in Norway will appear in court on Monday after admitting responsibility.
Anders Behring Breivik’s lawyer Geir Lippestad said his client would offer more information at the custody hearing.
“He believed his actions were atrocious but in his head they were necessary,” Lippestad said.
Breivik has been charged with both the bombing in central Oslo and the Utoeya island shooting.
The court will decide whether to keep the 32-year-old suspect in detention pending trial.
Norwegian police said on Saturday that Breivik was the author of a YouTube video in which he is seen wearing a wetsuit and pointing an automatic weapon.
He also penned a 1,500 page manifesto entitled “2083: A European Declaration of Independence.” It was posted online just before the Oslo bombing.
In the book, Breivik outlines his anti-Muslim and anti-immigration views.
In one passage, he writes: “Time is of the essence. We have only a few decades to consolidate a sufficient level of resistance before our major cities are completely demographically overwhelmed by Muslims.”
The book also includes detailed instructions on how to acquire materials to make bombs and photos of Breivik.