Five South Koreans have been arrested on charges of pocketing a large sum of money by routing international calls through the illegal usage of SIM cards, police said Thursday.
  
The suspects, including a ringleader surnamed Um, allegedly brought in 617 SIM cards from China and made a specialized device that routes international calls without the proper government approval, according to the Seoul Metropolitan Police Agency.
   
The SMPA alleges that the equipment automatically switches international call signals to domestic, and then again to international to trick mobile carriers, said the officers.
  
The suspects swindled nearly 1 billion won ($902,000) as broker fees from foreign mobile carriers from July 2013 to February 2015, according to the SMPA officers.

"It marks the first time that police have caught international call scams using such equipment like a SIM card box," said an SMPA officer in a statement. (Yonhap)