It has previously described the investigation as an attack on free speech.
The investigation into X began in January 2025 before being expanded in July that year after reports of sexually explicit deepfakes and holocaust denial content circulating on the platform.
X previously described the widening of the probe in a post at the time, external as “politically-motivated” and denied allegations it had manipulated its algorithm.
Prosecutors say they are now investigating whether X has broken the law across multiple areas.
Among potential crimes it said it would investigate were complicity in possession or organised distribution of images of children of a pornographic nature, infringement of people’s image rights with sexual deepfakes and fraudulent data extraction by an organised group.
The prosecutor’s office also said it was leaving X and would communicate on LinkedIn and Instagram from now on.
Musk’s social media platform has recently been subject to intense scrutiny over sexualised images generated and edited on the site using its AI tool Grok.
The images – often made using real images of women without their consent – prompted a barrage of criticism from victims, online safety campaigners and politicians.
The company eventually intervened to prevent the practice.
In late January, the European Commission announced an investigation into its parent company xAI over concerns about the images.
A similar probe had been previously launched by the UK regulator, Ofcom.