No study of the work of the Palme Commission, not even the government’s exhaustive investigation, has so far been able to explain how Christer Pettersson – an addict from Rotebro – became the main suspect. But in every version provided by Thure Nässén, the investigator who was instrumental in naming Pettersson a suspect, there is one common denominator: drug dealer Sigge Cedergren.

Christer Pettersson had been sigge Cedergren’s customer and they had known each other for some time. Cedergren placed Pettersson outside the movie theater during the night of the murder, gave the police information about a possible motive and a murder weapon.

But while he was one of the most important witnesses to the Palme Commission, Sigge Cedergren was actually an addled and run-down addict, according to people close to him.

”He started getting into some serious drugs. Primarily, the Polish amphetamines that were used to shoot up. It affected his mind. His brain wasn’t quite working,” says Kent Bängs, former Stockholm narcotics officer.

An Officer Comes Forward

During the past year, Mission Investigate has had meetings with a total of ten homicide officers who worked on the Palme Commission and saw the case against Christer Pettersson being built. Three of them claim that there were elements of witness manipulation in the investigation.

All three of them say that police officer Thure Nässén systematically provided Sigge Cedergren with information so that he would give the right answers in interrogations. None of these officers agreed to be interviewed. But we find another officer who is willing to come forward.

For nine years, Sören Moberg was an investigator in the Palme Commission.

”Thure Nässén over-interrogated some witnesses.

What does over-interrogation mean?

”You can’t interrogate someone more than 20 times. You can’t close a case by deciding ‘he is the one’. That is completely wrong.”

Officer: ”You can’t do this”

When Mission Investigate takes a closer look at the huge Palme Investigation, it turns out that Sigge Cedergren was heard by police no less than 43 times. Lisbet Palme, the only one to see the killer up close, was heard a dozen times.

The majority of interviews were performed by Thure Nässén, often without a tape recorder. The tapes of the interviews which were actually recorded have been destroyed. So there is no way of telling how Cedergren’s testimony evolved.

But during the first 11 interviews with Nässén, there is no indication of Christer Pettersson as the perpetrator.

Cedergren testifies that he passed the murder scene, heard the shots and saw a fleeing man. At first, he names the fleeing man as the famed thief Lars-Inge Svartenbrandt and then a police officer used in one of the witness lineups – but also singer Ted Gärdestad and finally Christer Pettersson.

”This is nonsense. These statements aren’t worth the paper they are printed on as far as I am concerned,” Sören Moberg says about the interviews.

”I’ve rarely seen anything this chaotic”

According to police telephone surveillance, Sigge Cedergren wasn’t even outside when the murder occurred. He was at home, speaking on the telephone.

”I have looked at more than 20 of the interviews held with Cedergren and I have to say, I have rarely seen anything as chaotic,” says Pär-Anders Granhag, one of Sweden’s premier experts in interrogation techniques, who has studied the Cedergren protocols.

He points to examples where Sigge Cedergren provides information that doesn’t match facts the police already know, and then gets help from Thure Nässén.

”Then the head interrogator says, ’Don’t stick to a previous story just to seem believable’.” So Sigge Cedergren is basically told to change his story.

No Interview with Nässén

”It’s a fine line,” says Pär-Anders Granhag, ”between wanting credible information, and manipulating a person to say things you want, which ’fit’ the investigation.”

”In light of all this, it is a mystery to me how they could value his information as highly as they did.”

Mission Investigate contacted Thure Nässén to allow him to respond to the charges of the investigation having been manipulated. He denies that he had fed information to addicts and does not want to be interviewed.

”You are so wrong that I think it’s sad. Listen, I have nothing more to say about this.”