The Svea Court of Appeal in September ordered a retrial in the case after Quick, who now goes by the name of Sture Bergwall, retracted his confession.

The court ruled that the absence of supporting evidence meant that the conviction was not beyond reasonable doubt. The prosecutor has now found that no such forensic evidence or witness testimony exists.

“There is no evidence which directly links Bergwall to the crime,” the prosecutor Olle Sohlberg said in a statement on Tuesday, formally dropping the charges.

A development which generated interest in the case was that it was found that small burned particles claimed by expert witnesses in the murder trial to be “most probably from a human, probably from a younger person”, were found to be pieces of wood and glue.

Thomas Quick has been convicted in six trials for the murder of eight people.

In 2008 he retracted all his confessions for the crimes and applied for his first re-trial. In 2009 the Svea court of appeal granted Quick a new trial for the murder of Yenon Levi in Hedemora in central Sweden in June 1988.

Quick was acquitted of Levi’s murder in September 2010.

Quick remains convicted of the murders of Charles Zelmanovits in Piteå in 1976, Johan Asplund in Sundsvall in 1980, Trine Jensen in Oslo in 1981, a Dutch couple called Stegehuis in Appojaure in 1984, and Gry Storvik in Oslo in 1985.

His next application will concern the murders of Trine Jensen and Gry Storvik.

Thomas Quick has been in psychiatric care since 1991.