Detectives yesterday claimed to have arrested four Jama'atul Mujahideen Bangladesh (JMB) operatives in the capital's airport and Khilgaon areas Sunday, and said one of them had been spying for a foreign intelligence agency for years.

The alleged spy Idris Sheikh used to maintain communication with an official of the agency with a "spy mobile" phone, said Monirul Islam, joint commissioner of the Detective Branch of Dhaka Metropolitan Police.

Idris and three other arrestees -- Mogbul Sharif, Md Salam and Mostafa Zaman -- all Bangladeshi citizens had been visiting and staying in Pakistan for years.

Detectives claimed that they recovered the so-called spy mobile and four other cellphones, three Bangladeshi passports, and currencies of some countries. 

At a press briefing at DMP media centre, Monirul said that analysing the "spy" phone of Idris they found evidences that he used to transmit all information from Bangladesh to the intelligence officer.

Besides, he used to communicate with an officer of a high commission in Dhaka of the same country, said a detective officer. He, however, did not disclose the name of the intelligence agency or the country.

"Apart from communicating with the intelligence officer over the phone, Idris met him in person too," he said.

Of the four, Idris and Sharif managed Pakistani citizenship during their stay in Pakistan in 1990 and 1989 respectively.

The DB official claimed that Idris toured to Pakistan from Bangladesh in 1985 through India and got its citizenship after marrying a Pakistani woman.

He participated in the 2002 Pakistan general election as a candidate under Pak Muslim Alliance party but was defeated. He then came back to Bangladesh in 2007 and joined JMB.

"In only last two years, he (Idris) made 48 trips to Pakistan," Monirul added. 

Their ultimate target was to carry out destructive activities and also to finance sabotage to destabilise the country and embarrass the government, he said.

Asked whether any High Commission is involved in destabilising the country, Monirul said, "We will let you know after further interrogation."

According to the detectives, Sharif went to Pakistan in 1985. Sharif, a frequent traveller to Karachi, had contact with Rohingya militant leader Abdul Kuddus Bormi, who is training Rohingya militants in Karachi, they claimed. He is involved in human trafficking and used to send Rohingyas with fake passports to Pakistan and others to Canada and Australia. Salam, who belongs to the Bihari community, also used to visit Pakistan while Mostafa was an assistant traffic inspector of Pakistan International Airlines.