Elin Krantz and her alleged killer were riding the same tram to the Hisingen neighbourhood near Gothenburg in western Sweden.
Shortly thereafter Krantz was raped and murdered in a wooded area not far from the tram stop, according to information from the investigation.
Krantz and a friend were heading home on the number 5 tram line from the Valand nightclub in downtown Gothenburg around 4am after a Saturday night out together, according to an account by the Aftonbladet newspaper at the time of the killing.
While Krantz's friend got off the tram at the Hjalmar Brantingsplatsen stop, the 27-year-old continued in the direction of Gropegårdsgatan. But she never came home.
A 23-year-old man was arrested shortly after the killing. On Friday he was charged with murder and aggravated rape.
According to prosecutors, the 23-year-old suspect hit and/or kicked Krantz with such force that she was left with contusions and haemorrhaging on her head, neck, arms, and legs.
The violence was so severe that it also caused nerve damage in Krantz's brain, resulting in a lack of oxygen.
The 23-year-old is suspected of having raped Krantz by holding her down and forcing her legs apart. He then allegedly dragged her body over uneven ground and then placed it on a large stone block, according to prosecutors.
Included in prosecutors' long list of injuries to Krantz are "burst membranes around the vaginal opening".
According to the prosecutors, the 23-year-old showed "extreme ruthlessness".
The man, who has been in custody for more than five months, denies committing the crimes.
At the start of his time in remand, he remained silent during questioning from investigators. After several months, he finally admitted that he was at the scene of the killing, but pointed to two other men.
He also admitted riding the same tram as Krantz, but it was only when they got off at the same stop that the two exchanged any words.
"They got off at the same time, he walked behind her. After a few hundred metres they parted ways," the man's attorney, Claes Östlund, told the TT news agency.
"He saw how she mets two other men, but he continued walking and sat down on a bench. As he sat there, he heard a woman scream. A short while later he got up and walked in the direction of the scream and came to the place where the woman met the two men. He saw then that the men were having sex with her.
"He then ran toward them and scared the guys away. He lifted up the woman. But she had fainted and is unresponsive. After a few minutes, the guys show up again and chase him away."