Norwegian authorities say the 32-year-old gunman who confessed to killing 69 people last month on a lake island has described the killings with “many new details” during a heavily-guarded visit to the crime scene.

Prosecutor Paal-Fredrik Hjort, speaking Sunday in Oslo, said gunman Anders Behring Breivik led police on a eight hour route that traced one taken during the July 22 shooting rampage on Utoeya island, 40 kilometers northwest of the capital. Authorities say the entire reenactment was filmed for possible use in court proceedings.

The 32-year-old has also admitted to setting off a bomb outside government offices in Oslo earlier the same day, killing eight people.

Video images in Norwegian media show the gunman arriving Saturday at the scene with authorities on the same ferry he used to get to the island last month. He was restrained in a rope harness and wore a bullet-proof vest.

He is seen pointing out locations along the route and simulating shots into the water, where scores of teenagers tried to escape the deadly onslaught.

Breivik’s lawyer has said his client admits the killings, but denies criminal responsibility because he believes the massacre was needed to save Norway and Europe from the influx of Muslims, and to punish politicians for embracing multiculturalism.

The killings were the worst mass violence in Norway since World War Two.