Detectives investigating the terror attacks carried out controlled explosion at Anders Behring Breivik’s rented property Police investigating the Norwegian terror attacks that left 76 people dead have detonated a stash of explosives at a farm rented by Anders Behring Breivik. Detectives believe the 32-year-old made the bomb that killed eight people in Oslo on Friday using fertiliser he purchased under the guise of being a farmer. The controlled explosion on Tuesday night came after police named four of the victims , including three caught up in the city centre bombing and a 23-year-old shot dead in the Utøya Island gun rampage. Police would not reveal the quantity of explosives found at the leased farmstead in Rena, about 100 miles north of the capital, but said the detonation was carried out safely. As the investigation continues, security officials have cast doubt on claims made by the gunman that he had accomplices who were still at large. At his first court appearance in Oslo on Monday, Breivik told a closed courtroom that he had links to “two other terror cells” . But Norway’s domestic intelligence chief Janne Kristiansen said no proof has yet been found to link Breivik to right-wing extremists in the UK or elsewhere. She told the BBC: “I can tell you, at this moment in time, we don’t have evidence or we don’t have indications that he has been part of a broader movement or that he has been in connection with other cells or that there are other cells.” The intelligence chief added that she did not believe the killer was insane, but calculating and evil, and someone who sought the limelight. At a press conference in Oslo on Tuesday, Johan Fredrikson, the chief of Oslo police, said that he still had no evidence that there was an accomplice or network behind the attacks despite an international investigation, including involvement by British police. Five days after the massacre, authorities and ordinary Norweigans are still jumpy. On Wednesday morning, Oslo’s main station was closed after a suspicious suitcase was discovered on a bus. All train and bus services out of the centre were halted while police investigated the suspect case, which turned out to be harmless. Also on Wednesday morning, Oslo police caused panic by putting out an alert saying they were looking for a “dangerous” and unstable man who claimed a connection with Breivik. But shortly after releasing the alert, police said they had wrongly connected the mentally ill man with Friday’s massacre. “This has nothing to do with Friday’s case,” a police official said after recalling the memo. “The news release was sent out in error. This is a routine mission by the police. The police have been criticised for their failure to reach Utøya island sooner on Friday after Breivik’s lawyer revealed the killer was surprised he had reached the island youth camp without being stopped by police – who took 90 minutes to arrive. It has emerged the nearest police helicopter available was not able to intervene because its pilots were on holiday. On Wednesday, the leader of Norway’s emergency police unit, Delta Force, defended its response to the atrocities, claiming the breakdown of the team’s boat didn’t cause any significant delay in its efforts to reach Utøya. Anders Snortheimsmoen told reporters that even though the assigned boat quickly broke down, the team immediately jumped into another, better boat. He says his team arrived at the harbour at the same time as local police and that the boat mishap caused “no delay”. Meanwhile, Norwegian investigators have assigned a whole unit to pore over the 1500-page manifesto Breivik emailed to more than 1,000 contacts less than 90 minutes before he launched his attack. One paragraph in the diatribe describes a detailed “survivor’s kit” which he claimed to be preparing in advance to help him break out of prison, including weapons, ammunition, nutrition, and cash. The Norwegian tabloid VG reports how Breivik describes plans for another terrorist attack, should he manage to escape from jail, including a “hit-list” of targets. Norway Anders Behring Breivik Europe Global terrorism Helen Pidd guardian.co.uk