A case in which Russia's richest man, Mikhail Prokhorov, was arrested by French police investigating prostitution has been dismissed due to lack of evidence of any crime, according to the billionaire's lawyer.

In January 2007, the now-44-year-old Prokhorov was detained by French authorities in the resort city of Courchevel, in the framework of an investigation into an international prostitution ring.

Three days later he was released without charge, following an investigation into the case. Still, the billionaire appeared in the case as a witness.

“I’ve said from the very beginning that the case is groundless. Its closure is only logical. I’m satisfied with the outcome and the explanations offered to me. As far as I know, the French justice system has in fact ruled the detention of my friends as illegal. For me it’s essential,” Prokhorov wrote in a recent entry to his internet blog.