Bhubaneswar, July 12: The Special Task Force (STF) of state crime branch today started interrogating the four accused arrested by Berhampur police on Saturday for suspected links with underworld don Chhota Rajan.

The accused, who are at present in four-day remand, are being interrogated at the STF office here.

The police have seized five Chinese SIM boxes from the possession of chief accused Pradeep Choudhury and his associates Laxmi Narayan Sharoff, Suresh Kumar Satpathy and Santosh Kumar Sahu. SIM boxes are used to divert international calls to local calls to avoid scrutiny.

Crime branch officials said that the STF, led by an additional police superintendent, was interrogating the four accused to find out their links with the underworld.

"The accused have claimed to have procured the SIM boxes from Hyderabad. We will interrogate them further to ascertain the source of the SIM boxes and whether they have also sold those to any others in the state," said a crime branch official.

The case assumed significance as it was the first incident of cyber crime executed using SIM boxes.

"We rely on mobile location of the accused to crack cases. But with the SIM boxes, it becomes difficult to trace the mobile calls," said a crime branch official.

Crime branch officials also suspected involvement of cellular network officials behind issuance of large number of SIM cards in fraudulent manner.