The victim told police she was attacked and raped by five men in the early hours of Sunday morning as she was walking home from the train station.
Following the attack, the woman called a friend who in turn alerted police.
While no arrests have been made in the case, police have secured forensic evidence which is currently being analyzed
According to the Expressen newspaper, the evidence consists of a used condom recovered near the scene of the suspected attack, although police have refused to confirm the nature of the evidence.
"All I can say regarding the securing of evidence is that we've secured evidence but I can't say what it is. It might be a condom and it might not be a condom," Martin Sjölie of the western district police told the newspaper.
Police are also reviewing security camera footage from the train station and nearby cash machines in hopes of gaining more leads in the case.
The victim was interviewed by police at the weekend and was able to provide a description of her attackers. Police also conducted a number of interviews with area residents.
"All I can say is that there are five assailants. As far as I know we don't have any suspected assailants; no one has been detained, no warrants have been issued," Sjölie told Expressen.