In a major boost to bilateral security cooperation, Bangladesh handed over top Ulfa leader Anup Chetia to India yesterday, 18 years after his arrest in Dhaka for trespassing.

Chetia, a founding member of one of India's top insurgent groups United Liberation Front of Asom (Ulfa), had been in prison since his arrest in Mohammadpur on December 21, 1997.

New Delhi had been pressing for his deportation for years so that he could join the on-going peace talks between the Ulfa faction led by Arabinda Rajkhowa and the Centre, according to Indian media. 

Finally, following personal intervention of Indian Prime Minister Narendra Modi and active involvement of National Security Adviser Ajit Doval, Chetia was sent back in pre-dawn hours from Kashimpur High-Security Central Jail, Gazipur.

Two of his associates, Babul Sharma and Shakti Prasad Goswami, who were arrested with him in Dhaka, were also deported.

Hours after Chetia was received by a team of Central Bureau of Investigation (CBI) in India, Modi spoke to Prime Minister Sheikh Hasina over the phone thanking her for her cooperation in fighting terrorism.

During the conversation, Modi also wished Hasina on Diwali, according to a Twitter post of his office. Indian Home Affairs Minister Rajnath Singh on Twitter also thanked Bangladesh government for its active cooperation in sending Anup Chetia to India.

Indian High Commissioner in Dhaka Pankaj Saran was in Delhi for the last two days as details of the handover were being worked out, sources said.

After his arrest in Dhaka, Anup Chetia was charged with illegal trespassing without passport, illegally keeping foreign currencies and a satellite phone and subsequently was sentenced to seven years in jail. His two associates faced the same charges and punishment.

The Ulfa leader had sought political asylum in Bangladesh thrice -- in 2005, 2008 and 2011.

Despite the expiry of his prison term, he was in jail under a 2003 High Court directive asking the authorities to keep him in safe custody until a decision was made regarding the asylum plea.

Chetia, whose original name is Golap Baruah, is wanted for murder, abductions and extortions in India. Hailing from Jeraigaon in Tinsukia district, he is a neighbour of Ulfa's armed wing chief Paresh Baruah, now believed to have taken shelter in Myanmar.

Forty-eight-year-old Chetia is considered to be the only person in the insurgent group who can take on Paresh Baruah, who is against the peace talks.

Yesterday, Home Minister Asaduzzaman Khan Kamal said the Border Guard Bangladesh (BGB) handed over the trio to the Border Security Force of India as their jail terms ended and Anup Chetia himself withdrew his petition he filed earlier with the High Court seeking political asylum.

Highly placed sources said they were deported through Dawki border in Sylhet.

The home boss primarily denied the handover, saying he was not aware of any such development. But around one and a half hours later, he said the government "freed" Chetia on completion of the jail term.

"Anup Chetia was detained under the law of this land and his jail term has completed. As he is a foreigner and he expressed his interest to leave the country, we have freed him," the minister told reporters at his secretariat office at noon.

"If any foreigner completes his/her jail term, we always communicate with the embassy concerned. As Anup Chetia completed his jail term and wished to return to India, we communicated with the Indian High Commission and released him. It is the matter of Indian High Commission, how and when he crossed the border."

 Although India and Bangladesh signed the extradition treaty on January 28, 2013, Chetia was not handed over under the treaty, he added.

The home boss quoted Chetia saying, "I am going back willingly and consciously and in good health."

Asked whether Chetia was handed over in exchange for prime accused of Naryanganj seven-murder Noor Hossain, now in a West Bengal prison, the minister said when the Indian government would say that Noor's jail term ended, he would be received by Bangladesh at the border.

Later in the day, Inspector General of Prisons Brig Gen Syed Iftekhar Uddin told reporters at the Department of Prisons that Chetia and his two aides served their term till 2004. But they still remained in jail as "released prisoners".

Foreigners, who complete their prison term but are kept in jails until having clearance from Bangladesh and their respective countries for deportation, are called "released prisoners".

He said Chetia applied twice for being sent back through the Indian mission instead of being deported through bordering area.

So the jail authorities handed him to an Indian embassy delegation at the jail gate on completion of all formalities.

After the latest release of the three, 80 more "released prisoners" of different countries are in jail in Bangladesh, Iftekher Uddin said.

According to Indian home ministry sources, the process of Chetia's deportation has been going on for the last six months, added our New Delhi correspondent. 

Earlier, Bangladesh sent back some other top Ulfa leaders, including Arabinda Rajkhowa, on December 2, 2009 through the border with northeastern Indian state of Assam. They have joined peace talks with Delhi.

Assam's Chief Minister Tarun Gogoi yesterday said Chetia hopefully would play an important role in the peace process. He added that the insurgent leader should be handed over to the state government because all cases against him are registered in Assam.

"We believe that he will play an important role in the peace process. We have been demanding extradition of Chetia from Bangladesh for fruitful discussions between the government and pro-talks Ulfa faction," Gogoi said in a statement.

Gogoi said he expected the central government to release Chetia like the state government did in the case of other pro-talks Ulfa leaders like Arabinda Rajkhowa to "expedite the peace process".

Peace parleys is believed to be in advanced stage and the government may sign a pact with Ulfa leaders before the next year's assembly elections in Assam where India's ruling BJP is aspiring for power for the first time.

Chetia's wife and children have already returned to Assam from Bangladesh.

Apart from Rajkhowa, Ulfa's self-styled general secretary Chitraban Hazarika, deputy commander-in-chief Raju Baruah, foreign secretary Sasha Choudhary, vice-chairman Pradip Gogoi and two other leaders Mithinga Daimary and Bhimakanta Burhagohain (now deceased) were out on bail after their brief incarceration.