Continuing with its probe to expose nexus between northeast terror groups and Naxals, NIA on Monday arrested a director of a private school at Merapani in Upper Assam's Golaghat district for his alleged links with Maoists.

Disclosing that director of Jatiya Vidyalaya ,Pallab Barbora alias Profull was picked up by NIA sleuths from his residence, authoritative security sources reported that Barbora a prominent human rights activist of the state was closely associated with left wing insurgency spreading its network in Upper Assam.

Bora was arrested by security forces in Jharkhand and brought to the state but managed to jump the bail.

With this arrest, six persons have been nabbed. Of them, three have been produced before a designated court in Guwahati after being chargesheeted.

Though NIA was officially tight-lipped about his role, sources in the probe agency alleged that Borbora was the key person who facilitated meetings between PLA and Maoists.

He is also alleged to be in the decision-making process of fixing training modules and venues for Naxals, they said.

NIA had filed on May 21 its charge sheet, which is the first documentary evidence submitted before a court of a nexus between northeast insurgents and Maoists.

The charge sheet was filed before the designated court of NIA in Guwahati against N Dilip Singh, Senjam Dhiren Singh alias Raghu and Arnold Singh under various sections of Unlawful (Activities) Prevention Act.

The NIA then arrested Asem Ibotombi Singh alias Angou of PLA from Odisha as he was alleged to have been functioning as 'secretary' of its 'External Affairs Wing'.

It is alleged that PLA had imparted training in handling of fire arms and communication devices to Maoist cadres in Saranda forest on Jharkhand-Odisha border in 2010.

On May 23, NIA had taken custody of Indranil Chanda, an alleged Naxal leader arrested by the West Bengal Police. He was in-charge of Maoist activities in Assam and key liaison between Maoists and PLA, the sources added.

Meanwhile, outlawed Ulfa hardliners condemned the arrest of Barbora while asking the human rights activists to launch an agitation opposing his arrest.

In a press statement issued on email, the Ulfa publicity in-charge Arunoday Asom claimed that Barbora was a prominent human rights activist of the state and his arrest was a gross violation of human rights.