The Malmö district court acquitted the man on charges of aggravated assault over a weekend of slave-like sex with the then 16-year-old girl.
The ruling is taken as a primary legal indication over whether a girl prone to self-harm is able to consent and submit herself to violent sex.
The issue of how much sexual violence is allowed between consensual sex partners had never been heard in the Swedish court system and experts in sadomasochism were called to testify in the hearing in Malmö district court.
The district court noted in its ruling that valid consent can not apply to aggravated assault, which in general can neither afford freedom from responsibility for the perpetrator. The court considered the level of violence to which the girl was subjected to be reduced to a classification of assault.
The court thus ruled that this was not a case of aggravated assault, and also noted that the girl had issued her consent of her own free will, observing that she had herself taken the initiative in contacting the man.
The 16-year-old girl came in contact with the man through a sadomasochism-themed website and later signed a “slave contract” in which she consented to being “used, abused and thoroughly humiliated”.
“I want to have a really hard master. Someone who won't wimp out,” the teen wrote the 32-year-old during their online chat, according to the Aftonbladet newspaper.
During their sexual encounter, which took place in January, the girl allowed herself to be locked in a cage and have clamps attached to her breasts, according to several media reports.
The 16-year-old was also hit with whips and rulers, and made to have oral sex until she vomited, according to Aftonbladet.
Police were alerted to the alleged assault when a relative of the teen noticed she had bruises all over her body.
The man and the girl spent ten days discussing what they wanted to do when they met, before she arrived to take part in their role play.
The girl was over 16-years-old and thus above the age of consent and the court ruled that it had not been proven that her age, her history of self-harm, or any other extenuating circumstance, rendered her unable to understand what she was consenting to, or that her consent was meant in all seriousness.
The court furthermore observed that the girl had previous experience of BDSM sex and thus knew what she was getting herself into.