The woman was found dead just before midnight on Monday in her apartment in Landskrona in southern Sweden, with multiple stab wounds to her body.
“It’s horrible in there,” said a police member to the Aftonbladet newspaper, reporting that blood traces ran from the room to the elevator.
The woman, who had previously lived in a foster home after escaping from family problems, had celebrated her 19th birthday in the apartment recently.
She reportedly moved to the apartment to build a new life for herself after having been plagued by family troubles.
Police arrested the woman’s 16-year-old brother after finding him outside the apartment, according to the paper.
It is alleged that the boy killed his sister for disgracing their family by having several boyfriends and trying to build a life for herself away from home.
“He thought that she brought shame to the family,” a friend of the victim told the paper.
The suspected murderer had also run away from the turmoil at their family home, and had also sought refuge in a foster home.
The boy’s lawyer said his client denies the charges.
“The police have presented a certain amount of evidence, but my client denies the crime,” said Urban Jansson to the paper.
Police were called to the apartment in the late hours of Monday night, and believe the call was made by the suspected killer himself.
The 16-year-old was already known to police for previous petty crimes, including theft of clothing from a clothing store last year.
Friends of the woman and workers at the foster home have described the woman as loving and popular.
”She always cared about her friends, and for those she loved. She put others before herself,” one friend told Aftonbladet.
The woman had sought help for some time from the Tänk Om (“Think again”) organization in Malmö, which fights against honour related violence.
The organization posted staff member’s deepest condolences on its website, referring to the incident as a “tragic honor killing”.
“This is a very heavy day for those near to her, and for everyone’s right to the freedom of choosing their own life,” the organization wrote in a statement.