Another “wide network” of Malta-based illegal online betting platforms were uncovered by authorities in Italy, the Malta Independent has reported.

The operation, dubbed Master Bet, has led to the house arrest of at least 13 people, while 46 others had their commercial assets seized. In addition, some 107 people were interrogated in connection with the alleged fraud.

According to police in Catania, Sicily, “millions of euros each month” were laundered through complex networks of gambling websites operated by two criminal groups through their gaming platform situation in Malta.

Investigators said groups owned Italian-facing websites, which were being operated without permits using platforms registered in Malta. Catania police were able to trace the operations back to the two organizations “by monitoring telephone calls and other forms of communication,” according to the report.