The book points to new evidence and reveals previously unpublished details concerning the murder, according to the Aftonbladet newspaper.
Palme was murdered in 1986 in Stockholm and Pettersson was arrested and jailed shortly after, following a major police investigation and after having been pointed out in a police line-up by Palme's wife.
However, Pettersson was released a year later due to a lack of evidence, specifically revolving around the murder weapon never being found. He was compensated for his time in jail, money he used to fuel his drug addiction, wrote the paper.
The new book, called “Palmes Mördare?” (“Palme's Murderer?”), suggests that this “lookalike” was actually the killer – based on new facts gleaned from a source involved in the investigation.
The “lookalike” was one of only 600 people in Stockholm who owned the exact type of gun used to kill the Prime Minister, a Smith & Wesson .357 Magnum. He also lived just 15 minutes away from the murder scene and was known to harbour a strong dislike for Prime Minister Palme.
When police knocked on the man's door in 2008 for an unrelated reason, he shot himself and died from his wounds, wrote the paper, adding that the man had been known to previosuly suffer from depression.