Sture Bergwall, a Swedish man long considered Scandinavia's most notorious serial killer has been released after being cleared of all charges.

Sture Bergwall, a Swedish man long considered Scandinavia's most notorious serial killer has been released after being cleared of all charges. Photo: AFP

A man once believed to be one of Sweden's worst serial killers was freed by court order on Wednesday after spending two decades confined in a mental institution after a string of false murder confessions.

In a series of trials between 1994 and 2001, Sture Bergwall was convicted of eight murders, despite there being no forensic evidence or witness statements, and confessed to many more.

But Bergwall, 63, later recanted his confessions, saying he made them to get attention and drugs, and prosecutors dropped the final murder charge in July last year.

"He has been detained for 20 years in a locked psychiatric clinic. It is a miscarriage of justice," his lawyer Thomas Olsson told Reuters.

Bergwall had been kept at the mental institution until now, waiting for a verdict on whether his mental health was good enough to let him out.

The case has gripped Sweden for years. The government launched a commission of inquiry last November looking into possible shortfalls in the legal system that may have resulted in Bergwall's convictions.

Bergwall and his lawyer will now start looking at whether to seek damages, Mr Olsson said.

Reuters