Sture Ragnar Bergwall (born 26 April 1950), also known as Thomas Quick from 1993–2002, is a Swedish man previously believed to have been a serial killer, having confessed to more than 30 murders while detained in a mental institution for personality disorders.

Journalists Hannes Råstam and Jenny Küttim and Dan Josefsson published TV documentaries and books about the murder cases; they claimed that bad therapy led to false confessions.

Dan Josefsson claims that a "cult"-like group led by psychologist Margit Norell manipulated the police and talked Sture Bergwall into false confessions.

With no eyewitnesses or technical forensic evidence to connect him to the crimes, Quick was convicted solely on the basis of his own confessions while undergoing recovered-memory therapy on benzodiazepines followed by police interrogations.

[8] [9] The involvement of therapists meant that Quick's early failure to provide anything more than a vague, confused and vacillating picture that gradually sharpened and focused was explained away as the result of repressed memories being retrieved as a result of therapy; e.g. in the judgment for the case of Therese one can read that the psychologist Christianson told the court that "Traumatic events are retained in the memory but there can be protective mechanisms that work in the unconscious to repress their recall."

Quick, who now reverted to his birth name of Sture Bergwall, was released from custody after having been confined for more than twenty years in an institution for the criminally insane, with conditions that he refrain from alcohol and narcotics.

Quick's lawyer Claes Borgström has been criticised for failing to protect his mentally disturbed client's objective interest in being judged not guilty.

In response to these accusations, Quick himself wrote an article for the Swedish newspaper Dagens Nyheter in 2001 in which he said that he refused to cooperate further with the authorities concerning all open murder investigations.

The handling of the Quick cases has been described as the "most scandalous" chapter of Scandinavian crime history, branding it as glaring incompetence, naiveté, and opportunism within the police and judicial system.

Quick withdrew all of his confessions in 2008 during the recording of a TV documentary,[16] made by prize-winning investigative journalist Hannes Råstam, who died shortly before his book version was published.

Thomas Quick, now having reverted to his birth name Sture Bergwall, recanted his confessions and requested the Svea Court of Appeal order a new trial for the murder case of Yenon Levi at Rörshyttan.

However, information had been withheld from the court that initially Quick had made many erroneous attempts to identify the murder weapon before finally giving an account that corresponded with police findings.

The documentary claims that Bergwall knew little about each murder, but was fed details during questioning, enabling him to build up enough information to persuade people he had carried them out.

What is Hidden in Snow) aired on Swedish television in 2018, directed by Kjell-Åke Andersson with Robert Gustafsson in the lead role as a police cold case investigator.

The Mikael Håfström thriller film The Perfect Patient premiered in Sweden in 2019, with David Dencik as Thomas Quick and Jonas Karlsson as the journalist Hannes Råstam.