Vincic, who oversaw matches involving Liverpool and Manchester City in this season's Champions League, was arrested in Bosnia and Herzegovina after being caught in possession of drugs and illegal firearms, and has now been linked to a wider operation that includes prostitution.
According to Croatian publication 24Sata, the Slovenian referee was taken into custody alongside self-proclaimed Serbian reality star and model Tijana Maksimovic, who is believed to have been the ringleader behind the operation.
While it is not apparent that Vincic was directly involved in the operation, he was arrested while trying to cross the border to Croatia with Maksimovic, while police also found nine women, various weapons and cocaine in a nearby cabin.
The 40-year-old, who has been a FIFA-listed referee since 2010, was in charge of three UEFA Champions League matches this season, including reigning champions Liverpool's 4-1 win over Genk in October.
