The conversation in question took place in the autumn of 2023, when the police made an unannounced visit to Høiby at his home, but the recording was not released until this week by Norwegian Se og Hør.
In the audio recording, one of the police officers is heard stating that they were ordered to make the visit by someone in the police top management – and that there are "more" who are concerned about Høiby's lifestyle, including his cocaine problem and connections to criminals.
The police officers are then heard saying that the visit constitutes a "special treatment" because he belongs to the royal family. The situation can become problematic since Høiby is the son of Norway's future queen, they say.
The leaked conversation raises questions about the police's professionalism and possible special treatment, notes Norwegian media.
The question is also who leaked the audio recording. According to Marius Borg Høiby's defender, Øyvind Bratlien, the 27-year-old is considering reporting the matter, reports Norwegian TV 2.
Høiby recorded the conversation, but he has never sent it to anyone. It should therefore not be possible for Se og Hør to obtain it legally, says Bratlien to the channel.
Se og Hør's editor-in-chief Ulf André Andersen writes to TV 2 that they obtained the audio recording "in a regular journalistic manner".
Marius Borg Høiby, who is Crown Princess Mette-Marit's son from a previous relationship, is being investigated for, among other things, assaulting two women he has had relationships with.