Mangs, who was found guilty of two counts of murder in July, had accused the lay judge earlier this month of bias and demanded that the Malmö District Court have a retrial.
“There were two reasons behind the bias objection. Partly that the lay judge was said to have received information from the police board during the investigation,” Malmö District Court head judge Lennart Strinäs told the Aftonbladet newspaper.
“We have spoken with the police who were on the board and they say that no details came forth about the investigation or about Mangs himself.
“The second reason was that at some point the police board expressed its appreciation for the professionalism of the police. But it was of a more general and overarching character and cannot, in our eyes, be seen as an indication of bias,” he said.
As a result of the court rejecting the killer’s demands, the guilty verdict against him can now come into force.
Mangs was arrested in November 2010 after a string of shootings that took place in Malmö against people of immigrant origin.
He was charged with killing two men of immigrant origin, aged 23 and 66, in 2003 and a 20-year-old Swedish woman who had been sitting in a car with an immigrant man in 2009.
He was also charged with 12 attempted murders in which he fired numerous shots with his Glock 19 pistol at homes, businesses and cars as well as out in the open, seriously injuring a number of people and coming close to killing many others.
In July, after a highly publicized trial and a lengthy criminal investigation, the court ruled that he was guilty of 13 of the charges, among these two murders, four attempted murders and three cases of making illegal threats.