Bedeviled for over 34 years by the mysterious killing of Olof Palme, the Swedish prime minister who was shot in the back by an unknown assailant on a quiet Stockholm street, Sweden’s judiciary finally made its case on Wednesday.
At a news conference in Stockholm, the prosecutor Krister Petersson said that there was “reasonable evidence” that the assailant was Stig Engstrom, a graphic designer at an insurance company, who killed himself in 2000, at the age of 66. He added that only a court could rule on whether Mr. Engstrom was guilty or not, but that since the suspect is deceased, there would be no court case.
But the prosecutor said he also could not rule out the possibility that Mr. Engstrom had acted as part of a larger conspiracy.
Mr. Petersson said he had reached his conclusions after an exhaustive investigation that he compared to those of the Kennedy assassination and the downing of Pan Am Flight 103 over Lockerbie, Scotland.
Mr. Pettersson, the journalist, among other things found a link between the killer and a weapons collector, a former military man who detested Mr. Palme and his socialist ideals. The prosecutor said that in 2017, the police found a weapon at the collector’s house matching the one that could have been used in the prime minister’s killing. But officials could not establish definitively that the gun was the murder weapon.
Mr. Petersson, the prosecutor, did not name the weapons dealer, as he is not a suspect. He also said the journalist’s findings had played no role in the investigation. But he allowed that “he came up with the same ideas we have came up with.”
There has been widespread criticism about the way the Swedish judiciary and the police have handled the case over the past decades. The mystery endured through six investigations and three commissions over the years, but Mr. Engstrom eluded suspicion though he had presented himself to the police as a witness to the killing.
As the cast of suspects waxed and waned, the case spawned numerous theories linking his death to dark, global conspiracies, many of them focused on South Africa.
It was Mr. Pettersson, a freelance journalist based in Gothenburg, who discovered that Mr. Engstrom had worked in a building near the theater where Mr. Palme was shot and had said he was present at the scene.
The journalist also found that Mr. Engstrom had been active in a shooting club, that he had political and private motives for killing Mr. Palme and that his personality matched a police profile of the likely killer. Mr. Engstrom was 52 at the time of the killing, and was frustrated with his lot in life.
“He had not advanced at his job,” Mr. Pettersson said in an interview. “He didn’t get the positions he felt he deserved. No family. No prospects in sight. So he was kind of a disappointed man at that point of his life.
“But he also had a drive to be recognized,” Mr. Petterson added. “To make something great of himself. He enjoyed every second of being in the media.”
At the time of the killing, investigators were focused on the suspected complicity of Kurdish militants, and Mr. Engstrom was not taken seriously, according to Mr. Pettersson.
Mr. Pettersson said he had investigated the case for 13 years before concluding that Mr. Engstrom was the killer.
“He has the right timing, the right clothing; he has unique information, he lied, he had close access to guns of the right type,” Mr. Pettersson said. “He was right-wing and Palme unfriendly,” he added. “He had a deep political interest and a deep anti-Palme sentiment.”
Mr. Pettersson said that he handed over his findings in late 2017 to the police, and that their investigation of Mr. Engstrom had been reopened based on that material. Mr. Petersson, the prosecutor, led a small team of detectives who took DNA from relatives of Mr. Engstrom, searched his former house and interrogated several people the police not heard from before.
The prosecutor is well known in Sweden for his investigations of the fatal knife attack of the Swedish foreign minister Anna Lindh in 2003 and the 2014 killing of Swedish journalist Nils Horner in Kabul, Afghanistan.
But as with other leads in what is sometimes described as one of the world’s longest police inquiries, the findings of the journalist also highlighted major blunders by the Swedish police.
From the first minute that fatal evening, mistakes were made, said Inga-Britt Ahlenius, a former under secretary general of the United Nations, who was a member of the last of three committees scrutinizing the police investigation.
“It was a failure from the start,” she said in a phone interview. “Everything went wrong from the beginning.”
The crime scene wasn’t fenced off from the public, the alarm came late, there was chaos in the situation room, and reports were not properly documented, she said.
Making matters worse, the regional head of the police Hans Holmer, took charge of the initial investigation without clear authority, bypassing normal procedures, Ms. Ahlenius said.
“What should’ve been done by the attorney general and the prosecutor was done by one man who only did that because he was a charismatic figure,” she said.
A year was lost, and Mr. Engstrom was never questioned.
“When I now read the documentation, he early on presented himself as an important witness,” Ms. Ahlenius said.
Mr. Engstrom’s former wife, whom he divorced in 1999, dismissed the idea of his involvement in the killing of the prime minister.
“It is out of the question,” she told the newspaper Expressen in 2018. “He was not that kind of person, that’s for sure. He was too much of a coward. He wouldn’t harm a fly.” The Swedish news media are not identifying her by name.
A known petty criminal called Christer Pettersson (no relation to the journalist) was jailed for life in 1989 over the assassination, but he won an appeal later that year and died in 2004.
Mr. Engstrom even testified in defense of Christer Pettersson.
“In some ways it was a stroke of genius, because Engstrom placed himself as a witness,” said Mr. Pettersson, the journalist. “Each time he told his story, he established himself as a witness and made it more difficult for the real witnesses of the crime scene and investigators.”
The case was always a magnet for conspiracy theories, many of them related to Mr. Palme’s political credentials as an idealist who fought for perceived victims of injustice, particularly in the developing world.
At the height of the Cold War, he sought a “third way” between East and West, and was criticized for tilting too much toward Moscow. He opposed the war in Vietnam and denounced apartheid in South Africa.
South Africa loomed large in theories of his killing because Sweden became a conduit for clandestine financial support to foes of the white government in Pretoria. After the collapse of apartheid in 1990, a white former security officer, Col. Eugene de Kock, alleged that an agent of the apartheid government had murdered Mr. Palme because of his stance against racial segregation.
But that was only one of many theories.
In the end, the Swedish judiciary says, it was all the work of one man, Mr. Engstrom.
Mr. Pettersson, the journalist: “He wanted attention.”
The prosecutor, Mr. Petersson, acknowledged that there was a chance that his finding would not be accepted by the general public. “It has been enough for us to present this case,” he said. “We can’t stop anyone from having opinions about what we have found.”