The woman disappeared after a barbecue party near the village of Långshyttan in the rural Dalarna region last summer. She was found dead two weeks later in a water-filled mine shaft.
Falu District Court found four people guilty of murder. Newspaper Expressen reports that it sentenced Joakim Hessling, 26, who stabbed the victim, to 17 years in jail.
Daniel Viberg Wahlgren, 21, and Martin Broling, 24, were sentenced to 16 years in jail. Benita Hokkanen was handed a shorter punishment – 12 years – because she was only 20 at the time the murder was committed.
Two people – Per-Olov Höflinger, 46, and Mats Hedin, 45 – were found guilty of complicity in murder and sentenced to ten years in jail.
Another three women were convicted of failing to reveal murder, one woman was freed of all charges and one man was convicted of “less serious crimes”, wrote the court in a statement.
The court heard that the victim had lent money to some of the people charged, who did not appreciate her attempts to get the money back. In mid-June last year they decided to kill her.
They invited her to a barbecue party at a lake. Afterwards, they sat down in a car where some of them strangled her with a rope while singing along to the song 'Forever Angel' on the car stereo.
She was eventually stabbed to death after they noticed she was still breathing. The body was wrapped in plastic and thrown down the mine shaft. The group then used her bank card to make several purchases and took items from her apartment, reports Swedish news agency TT.
The lawyers for Broling, Hessling and Wahlgren told the newswire that they would likely appeal the sentence. None of the other people's lawyers immediately commented on whether or not they would appeal.