Who Killed Olof Palme?

Background

Olof Palme, Sweden's Social Democratic Prime Minister, was walking home from a cinema in central Stockholm with his wife Lisbeth on the evening of 28 February 1986, having dismissed his bodyguards for the night, when an unidentified gunman approached from behind and shot him once at close range on Sveavägen, a main city street. Palme died almost instantly; Lisbeth was wounded but survived. He was the first Swedish national leader assassinated since King Gustav III in 1792, and the killing shocked a country unaccustomed to political violence.

The subsequent investigation became one of the largest and most expensive in Swedish criminal history, examining well over a hundred formal suspects and thousands of tips over four decades, hampered from the outset by early investigative missteps: lead investigator Hans Holmér fixated for nearly two years on a theory implicating Kurdish PKK militants, a line later abandoned as baseless, while the crime scene itself was inadequately secured and the murder weapon was never recovered.

Main Theories

Christer Pettersson: convicted, then acquitted

Christer Pettersson, a career criminal with a history of violence and alcohol abuse, was identified by Lisbeth Palme in a police lineup and convicted of the murder by a Stockholm district court in July 1989. The Svea Court of Appeal overturned the conviction the following year, finding the prosecution had never produced the murder weapon, that Lisbeth Palme's identification came only after she had already seen Pettersson's photograph in the press, and that police had conducted the identification procedure with what the court called extremely serious errors. Sweden's Supreme Court declined a prosecutor's 1998 request to reopen the case, ruling the new evidence offered insufficient grounds for a retrial. Pettersson died in 2004, having never been legally found guilty.

The Engström identification, and its 2025 reversal

Stig Engström, an advertising graphic designer who worked for the Skandia insurance company near the crime scene, had for decades presented himself publicly as one of the first witnesses on the scene, and was only briefly investigated as a suspect before being set aside. When chief prosecutor Krister Petersson formally closed the investigation in June 2020, he named Engström — known in Swedish media as "Skandia-mannen," the Skandia Man — as the most probable gunman, citing Engström's access to a similar handgun, his movements that night, and inconsistencies in his own account, while explicitly acknowledging the case against him would have been too weak to bring to trial even had Engström, who died in 2000, still been alive.

That conclusion did not hold. On 18 December 2025, Lennart Guné, Sweden's director of public prosecutions, stated publicly that naming Engström had been a mistake, that the evidence pointing to him was insufficient to support the 2020 conclusion, and that he should no longer be regarded as the case's main suspect — while confirming that the investigation file itself remains formally closed rather than reopened. The reversal leaves the case in an unusual position: the only suspect ever officially named by prosecutors as the likely killer has since had that finding withdrawn, with no successor candidate proposed in its place.

Political-assassination theories: South Africa and the PKK

Because Palme was an outspoken critic of apartheid South Africa and a supporter of the African National Congress, investigators and journalists pursued a theory that South African intelligence ordered his killing. Records that surfaced after apartheid's end confirmed South African security services monitored Palme and regarded him as a significant adversary, and Eugene de Kock, a convicted commander of an apartheid-era police death squad, claimed during his own 1990s trial that agent Craig Williamson had organised the assassination under an operation he called Long Reach. De Kock offered no corroborating documentation or witnesses, and no Swedish or international investigation has substantiated the claim to evidentiary standard.

The Kurdish-militant theory that consumed the investigation's critical early years originated with lead investigator Hans Holmér's belief that PKK members were retaliating for Sweden's designation of the group as a terrorist organisation and its deportation of some members. A raid on a Kurdish community centre and a handful of arrests followed, but the theory collapsed for lack of evidence and was formally abandoned; some commentators regard the years spent pursuing it as the investigation's single greatest strategic failure, since it diverted resources during the period when physical evidence was freshest.

Current Consensus

No theory has met a Swedish court's standard of proof, and the case remains, in the prosecutors' own words as of December 2025, closed but unsolved. Pettersson's conviction was judicially overturned; the Engström identification was publicly withdrawn by the same prosecution authority that made it; and the South Africa and PKK theories, while each resting on a documented sliver of real intelligence-service interest or investigative attention, have never produced conclusive evidence. Unlike who killed JFK or who killed Robert F. Kennedy, both of which reached an official verdict that has stood through decades of appeals even as some evidence remains disputed, the Palme case has no standing official conclusion at all — its most recent formal narrative was retracted by the state itself less than a year before this was written.

Why This Mystery Endures

The Palme case occupies an unusual place even among unsolved political assassinations: rather than a single official verdict that dissenters have chipped away at for decades, as with JFK and RFK, Sweden's own prosecution service has named and then un-named a prime suspect, leaving the country's most-investigated crime with no settled narrative to react against at all. That reversal, delivered by the state nearly forty years after the killing, has kept the case in Swedish public life in a way a quietly shelved file never would.

It also endures because of what Palme represented: a prominent, divisive international voice against apartheid and Cold War-era power blocs, killed in a country that saw itself as uniquely safe from this kind of violence. The absence of bodyguards that night, the missing weapon, and the years lost to a discredited investigative theory all read, in hindsight, as a chain of ordinary human error rather than conspiracy — yet the sheer scale of the investigation that followed, and its repeated failure to produce a conviction that survives review, is what keeps the question alive for each new generation of Swedish journalists and true-crime audiences.