The public prosecutor is scheduled to file official charges in the case later on Wednesday but the men’s release suggests that they are no longer suspected of murder or manslaughter.
The girl died after falling from a fourth floor balcony in the city’s Fosie district.
Witnesses told police that the fall was preceded by a heated argument in the apartment where the girl and the two men lived.
The girl’s 38-year-old stepfather and 19-year-old brother were arrested in their home after the incident.
Police and prosecutors were initially basing their investigations on the hypothesis that the girl was the victim of an honour killing.