Singh, who is from Kumargram in Jalpaiguri district that borders Assam, along with other KLO leaders had managed to flee to Bangladesh during a joint operation by the Indian and the Bhutanese armies in 2003 against the KLO and ULFA cadres, who had set up camps in Bhutan jungles. Singh has several murder charges pending against him in north Bengal districts, sources in the state police said. 

Singh first surfaced as a chairman of the KLO in 1995 with bands of Rajbanshi youths joining the organisation and demanding six districts of Bengal and four of Assam to be carved out as a separate Kamtapur state. The KLO had a strategic tie-up with the ULFA and continues to be heavily patronised by the Assam outfit till date. Security agencies claim that the ULFA used to share its camp with the KLO in Bhutan hills and extended all support the outfit, which even carried out some select killings in north Bengal, particularly the one in Dhupguri where a CITU office was attacked in 2003.

Police officials said Singh was first arrested by the Assam police in 1999 but managed to get out of the custody after an alleged deal that he would ensure the surrender of a large of armed underground cadres if he was let off. However, after release, he once again went underground. Police sources said Singh married one of the KLO women cadres and both moved together.

Singh had a committed core KLO team, many of whose members came from his village in Kumargram. Prominent among those were Milton Barman, Hiten Roy, Rahul Roy and Rabi Rajbanshi.

However, after the joint operations in Bhutan jungles during which many cadres were arrested from the camps, the group disintegrated and its activities dwindled. But the core team was said to be hiding in Bangladesh and made occasional forays into north Bengal districts.

In 2009, some leaflets under the letter head of the KLO were reported to have been recovered from the bordering areas of Assam-Jalpaiguri-Coochbehar. The group was trying to extort money in the bordering areas.