Sture Bergwall, who was freed this week after over 20 years locked up as Sweden's most prolific serial killer, said on Friday that his lawyer was preparing a claim for damages.
"What happened was lamentable, we're talking about murder verdicts in eight cases, something that should not happen," he told AFP in an email interview, two days after his release, adding that his lawyer had started to work on a claim for damages.
"The Swedish judiciary has been naive ... It's very frightening that I could have been convicted -- and of course it raises the question of how many more innocent people have been convicted."
Sture Bergwall, 64 -- who used the alias Thomas Quick during the 1990s when he confessed to cannibalism and more than 30 murders -- was convicted to life imprisonment for eight of them and held at a psychiatric ward in Säter in north central Sweden since 1991.
He was later cleared of all the murders due to lack of evidence, amid revelations that he had been heavily medicated at the time of the confessions and had made them in return for more drugs and in order to seek attention.
As a free man he said he would spend his time walking in the countryside and writing a new book -- a follow up to his 2009 book "Thomas Quick is Dead", a phrase he has often used to describe the point where he dropped the pretence of being a psychotic killer.
That point came in 2008 in a Swedish TV documentary in which he withdrew his confessions.
By then he had earned an international reputation as Sweden's Hannibal Lecter.
"As Thomas Quick the comparison is maybe true but Thomas Quick is dead and there ends all similarities," he told AFP.
The court ruling that freed Bergwall said he still suffered from the same "personality disorder" and needs psychiatric treatment as an outpatient, which he contests.
"The chief medical officer and the whole forensic psychiatry unit is fighting for its reputation. They could hold me locked up year after year and now they don't hesitate to keep to a false diagnosis that others have completely rejected," he wrote.
"It's shameful and a part of this legal and healthcare scandal."
But some analysts suggest that a claim for damages may be far from straightforward given that Bergwall contributed to putting himself behind bars by confessing to crimes he did not commit.
His convictions have been dubbed Sweden's greatest miscarriage of justice in recent times because of the swiftness with which he was found guilty of the eight murders, which occurred between 1976 and 1988.
A number of high-ranking opposition politicians and legal experts have called for an independent commission to examine how Swedish courts could have convicted him despite the lack of evidence.
Justice Minister Beatrice Ask announced an inquiry in 2013.