Norwegian writer Kjetil Stormark has published a book based on the hacked e-mails of Anders Breivik, Norway’s VG newspaper reported on Monday.

The book, headlined “Mass Killer’s Private E-mails,” is based on more than 7,000 e-mails from Breivik’s four accounts that Stormark received from Norwegian hacker group Noria and handed over to police.

“It was striking how many words of support came from people who agreed with Breivik in his political views, many people chose to express [their support] shortly after his attacks. So, the book should become an eye opener for many people,” Stormark told reporters.

He also said that some of the e-mails suggested that Breivik was influenced by other people shortly before July 22, 2011, when he bombed government buildings in Oslo and opened fire at a youth camp on Uteyya Island, killing 77 people in total.

“His contacts suggest that there could be some psychological involvement, that there were people who have motivated Breivik to do what he did on July 22,” he said. “And if there is even a slightest chance that the July 22 attacks can occur again, then this case must be investigated further.”

Breivik, who was charged with "acts of terror," has told the court what he did was "cruel but necessary" to protect Norway from a wave of multiculturalism and a "Muslim invasion."

On August 24, 2012 a court in Oslo sentenced Anders Breivik to the maximum 21 years prison.