Breivik, in a bulletproof vest and tethered by a rope, was seen pointing out where he fired shots. Police later said he showed no remorse on returning to the site of the massacre.
The 32-year-old far-right extremist admits the killings but denies any criminal guilt. He believes he is in a war against Western ideas and democracy, as well as Muslim immigration in Europe, and that the killings were “necessary”.
Police spent eight hours on the island of Utoya with Breivik and filmed the reconstruction to use as evidence.
Norwegian prosecutor Paal-Fredrik Hjort Kraby said Mr Breivik had remained calm and co-operative throughout.
He added: “Our assumptions that his presence at Utoya would jog his memory was correct. Many new details emerged from his explanations. The suspect showed he wasn’t emotionally unaffected by being back… but didn’t show any remorse.”