Guwahati, Sept. 13: The National Investigation Agency (NIA) has summoned Ulfa (Independent) chairman Abhijit Asom alias Mukul Hazarika to appear before it for questioning in connection with a case registered against the outfit.

An official source told The Telegraph that the NIA had served the notice, issued under Section 41 (A) CrPC, to his relatives yesterday at his ancestral house in Kaxori gaon in Puranigudam area under Samaguri police station in central Assam's Nagaon district, about 120km from here. Through the notice, the NIA has asked the Ulfa (I) chairman to come to its Guwahati branch office at 1pm on September 30 to answer certain questions related to the case 4/2013 registered at the agency's Guwahati branch in the Lachit Nagar area.

The case was registered in connection with the illegal and anti-national activities of the Paresh Barua-led Ulfa (I).

The source said the notice was issued as part of an official procedure and failure on his part to comply with the notice will subsequently lead to issue of an Interpol red corner notice against Asom. According to the source, Abhijit Asom, who is also known as Abhijit Barman, is a 68-year-old doctor who lives in the UK and his real name is Mukul Hazarika.

"According to information available with us, he completed his MBBS from Gauhati Medical College in 1970 and left for the UK around 30 years ago," he said. According to his relatives based here, the last time he came to Assam was for a few days in 1983 when his father expired and after that they had neither seen him nor had any contact with him.

Security and intelligence agencies said he lives in the UK along with his wife and children. According to unconfirmed reports, he works at a private hospital in Billingham, England.

"Even before he was appointed Ulfa (I) chairman, he was carrying out work for the outfit abroad and is known to be close to Paresh Barua," the source said.

The NIA is trying to tighten its noose around Asom to arrest him and bring him to India to face trial. Paresh Barua appointed him the outfit's chairman after a large number of Ulfa cadres led by Arabinda Rajkhowa joined peace talks with the Centre in 2013.

"Mukul Hazarika had highlighted the problems of Assam in UN meetings and had raised the alleged human rights violations by security forces in Assam during anti-insurgency operations," the source said. The NIA notice was signed by additional superintendent of police (NIA), Guwahati, Subhasish Baruah, who is the investigating officer of this case.