Marius Borg Høiby was arrested shortly after midnight on Sunday, August 4, by Norwegian police. A friend of the assaulted woman is said to have alerted the authorities that the Crown Princess's son had assaulted his girlfriend and vandalized her apartment.
The charges are "bodily harm" – the Norwegian justice system's least severe term for violence – and vandalism.
The Norwegian Royal Court's communications director, Guri Varpe, tells Aftenposten that they do not want to disclose the type of contact the Crown Princess had with the victim.
"We do not want to go into details, as it is private", writes Varpe.
Marius Borg Høiby has, on the advice of his lawyer, chosen not to comment on the incident and was released on Sunday afternoon pending trial.
According to the police, there is no information that the woman suffered serious injuries, but she did seek hospital care, writes NTB.
Marius Borg Høiby has no royal title and has chosen to live his life out of the spotlight. His father is Morten Borg, with whom Crown Princess Mette-Marit lived before she became involved with Crown Prince Haakon.