Arne Treholt

Treholt was placed under surveillance by Norwegian counterintelligence services for several years of his career in the Norwegian Institute of International Affairs (NUPI) and the Norwegian ministry of foreign affairs. On 20 January 1984, he was arrested by Ørnulf Tofte, head of counterintelligence, at Oslo Airport on his way to Vienna to meet with KGB officers.

The police conducted two searches of Treholt's apartment. In May 1982, they found 10,000 USD in a suitcase. In August 1983 they found 30,000 USD in the same suitcase. Treholt and his lawyer later alleged that Norwegian counterintelligence services produced this evidence themselves, and that the police and the judges conspired to cheat with the cash evidence, to make it appear as if the money came from the KGB. These allegations have been refuted as untrue. Furthermore, Treholt during the trial admitted to having received "expenses" from the KGB, but claimed that it could "only" have been 26,000 or 27,000 USD.

Tapes from the trial, that were released in 2014, show that the notes in the suitcase were 50- and 100-dollar notes, and not as the verdict states: 20- and 50-dollar notes.[8]

Following a much publicized trial presided over by Astri Rynning, Treholt was convicted of treason and sentenced to 20 years in prison, one year short of the maximum sentence allowed under the Norwegian penal code. The conviction included espionage for the Soviet Union and Iraq, and high treason.

Treholt was convicted and sentenced for passing classified material to KGB in the period 1974–1983 and to the Iraqi Intelligence Service 1981–1983. The sentence also encompassed handing over secrets obtained at the Norwegian Joint Staff College where he was enrolled with authorization from the non-socialist coalition government. Despite the fact that the government of Prime Minister Kåre Willoch knew that he was under suspicion of espionage, he was admitted so as not to reveal the suspicions harboured by the authorities.

The trial led to a heated and extensive public debate about the Treholt case in Norway. The controversy concerned the evidence, and lack thereof, against Treholt, the conduct of the police and prosecuting authorities, and what was viewed as lenient treatment of Treholt while he was under suspicion.

Ila Prison

Treholt was incarcerated in Drammen Prison from 1984 to 1985. He was transferred to Ila Prison, a maximum security prison, in 1985. In 1986, prison officials discovered that he planned to break out, and he was swiftly transferred to another maximum security prison for longterm inmates, Ullersmo Prison.

On 3 July 1992, he was reprieved by the Labour government of Gro Harlem Brundtland. His pardon by Brundtland's Labour government in 1992, was controversial.[9]

Treholt was imprisoned for more than eight years.

On 15 December 2008, the Norwegian Criminal Cases Review Commission ruled that the case would not be reviewed.[10] The decision was final and could not be appealed. As a result of the decision, the prosecutor who handled the case in 2008, Stein Vale, wrote a book to summarize the case. The book – Teppefall i Treholtsaken ("Curtain falls on the Treholt case") – was published in September 2009. The chairwoman of the review commission, Janne Kristiansen, was appointed head of the Norwegian Police Security Service, the descendant organization of the Police surveillance service (Politets overvåkningstjeneste). Kristiansen and the PST would be defending the former POT from allegations of evidence tampering later on.

In September 2010, a new book by the con artist Geir Selvik Malthe-Sørenssen, who then claimed to be a private investigator, claimed that the searches of Treholt's apartment had not taken place and that one of the pieces of evidence presented in court had been fabricated by the police. On 18 September 2010, the Norwegian newspaper Aftenposten wrote that an anonymous former counter-intelligence employee claimed Treholt's and his lawyer's claim of evidence fabrication was true, but a few days later the anonymous alleged former employee withdrew many of his claims, stating that he did not know.[11] The Attorney General asked the Criminal Cases Review Commission to look at the case again in light of the recent claims.[12] The Attorney General stated that he did not believe the outcome of the case would have been any different without the evidence in question.[13] Malthe-Sørenssen was publicly exposed as a fraudster in 2016, and his alleged source was revealed by Verdens Gang to be a used car salesman and convicted murderer and con artist with no connection to the Treholt case, who was paid by Malthe-Sørenssen to impersonate a police security service employee.[14][15][16]

On 24 September 2010, the Norwegian Criminal Cases Review Commission decided to reopen its investigation of the case, previously closed in 2008. On 9 June 2011, the commission decided that the Arne Treholt criminal case would not be reopened. Based on interviews with 29 witnesses (18 of whom were former police investigators who had been involved in the Treholt investigation) as well as forensic studies of photographs, negatives and documents, the commission unanimously concluded that there was no basis to suggest that evidence against Treholt had been tampered with or had been fabricated. In a 59-page document, the commission completely discounted the allegations made in the 2010 book.[3] After the verdict, PST-director Kristiansen, who had denied re-opening the case in 2008, demanded an apology from Treholt's supporters. The demand was rejected.

In 2014 Treholt's lawyer Harald Stabell claimed to have been tipped off by an employee of Police Security Service that his law office had been under audio surveillance in 2010 and 2011.[17] After Geir Selvik Malthe-Sørenssen had been exposed as a fraudster in 2016, Stabell stated that the source of this claim was Malthe-Sørenssen and not an employee of the Police Security Service.[18][19]