CCTV footage of Anders Behring Breivik parking his van and walking off before a massive bomb inside exploded has been shown publicly for the first time.
The security camera video from July 2011 also contains pictures of the significant damage caused by the device, which weighed nearly a ton and killed eight people, as well as injuring dozens of others.
Norwegian mass killer Breivik, wearing a security guard's uniform, is seen parking his white van at the entrance of a building that housed the Prime Minister's offices. The PM was not there at the time.
Breivik gets out of the vehicle in the capital Oslo and briskly walks away.
He then got into a second vehicle, a grey Fiat van, which he used to drive to the nearby island of Utoya where he gunned down 69 people, mostly teens, at a Labour Party youth camp.
A security guard at a government building said of the Oslo footage: "My colleague got a call from the reception at the high-rise building (PM's office). At the same time I saw the white van on the monitor in front of me.
"It is normally only the Prime Minister and the bodyguards who park there. But every day we get cars parking there without permission so we need to chase them away."
The guard added: "It looks like a guy dressed as a security guard coming out of the car.
"I see he has the usual reflex markings on the trousers and it looks like he has a circular logo on his arm, so I believe it is a uniform from a security company. I see that he calmly leaves the car and walks away."
The guard said he zoomed in on the registration number and was about to send a text to the motor tax office to find out which security company it belonged to when the explosion happened.
Photographs of Breivik parking the van had previously been released and footage was shown during his trial earlier this year, but this was the first time the video was released publicly.
It is part of a documentary that Norway's public broadcaster NRK will air on Tuesday evening.
The programme also features comments by the security guard on duty that day.
On August 24, Breivik was declared sane and sentenced to Norway's maximum sentence of 21 years in prison - a sentence that can be extended indefinitely if he is deemed a continued threat to society.
Breivik confessed to the attacks, calling them "cruel but necessary" to protect his country from the multiculturalism his victims embraced and which he hates.