A pin-size in-ear speaker attached to a mobile phone carried in the exam taker's underwear was how an interstate gang leaked competitive exam question papers, Patna police claimed on Wednesday.

The cops said they busted the Patna wing of the racket - that also encompasses Haryana - with the arrest of eight men from near Lohiya Park.

The gang was behind the attempt to leak the question paper of the National Eligibility-cum-Entrance Test (NEET) for medical colleges as well as the leak of the Staff Selection Commission's MTS exam for central departments which was held last Sunday.

"The gang has confessed its involvement in leaking the SSC MTS question paper," said Patna SSP Manu Maharaaj. "The question paper and answer sheets were provided to them from Haryana and they were in touch with candidates in Bihar.

"The gang used to provide an the size of a pin to candidates," the SSP explained. "The speaker was inserted into an ear and was hardly visible. The speaker was attached to a shirt button."

Though the police claimed the speaker used to work like a magnetic field, experts said it was more likely it was a bluetooth speaker that could be operated from the shirt button. The gang members told the unscrupulous candidates the answers by calling up the phone hidden in the exam taker's underwear.

"The gang was active for four years and had helped candidates clear examinations such as for the SSC, railways, and others," said Patna ASP (operation) Rakesh Dubey.

The arrested men are Shambhu Prasad, Nitish Kumar, Dilip Kumar, Rajiv Kumar Ranjan, Santu Kumar, Rakesh Ranjan, and two men with the same name: Manish Kumar. One Manish, who the cops said is the kingpin, is learnt to have confessed to involvement in leaking the SSC paper and said that the answer sheets were provided to them from Haryana. Manish also confessed to the NEET attempt. The gang used to charge each unscrupulous candidate Rs 12 lakh.