In an interview on the news magazine programme Aktuellt, the girl's mother explained that she long had concerns about her 19-year-old son, who has been in custody on suspicion of murder since last Wednesday, along with the girl's 38-year-old stepfather.
“I had contacted both social services and the school several times about the problems with my son, the girl's brother,” the mother said to Aktuellt.
“But they told me my son was my problem.”
The night of the incident, witnesses reported hearing a heated argument from the fourth floor apartment and seeing the girl standing on the balcony with her back toward the railing.
Suddenly, the girl went backwards over the balcony and fell to the ground, dying instantly.
“I couldn't control my son's anger. He demanded that she attend to him all the time. Despite my talks with the school about the problem, my son and my daughter were placed in the same school,” the mother said.
“There he watched over her constantly. She wasn't allowed to leave the classroom with other students and she wasn't allowed to laugh.”
Prosecutors expect to file official charges in the case on February 20th.