The NIA on Monday formally arrested Lokesh Sharma, already in judicial custody in connection with the Samjhauta train bombing case, for his alleged role in the 2008 Malegaon blast.

Sharma was produced before the special MCOCA court of Y D Shinde who remanded him to NIA custody till March nine. The special court had issued a production warrant against the accused on February 23.

The agency said Sharma needs to be questioned in connection with the September 29, 2008, Malegaon blast in which six people were killed.

NIA had failed in its attempt to seek his custody from the Panchkula court on February 22.

While officially the probe agency, formed in the aftermath of 26/11 Mumbai attacks, was tightlipped, sources privy to the developments said Sharma's questioning was necessary after the interrogation of Kamlesh Chouhan, an alleged planter of bombs in the Samjhuta train.

Sharma, a close associate of Sunil Joshi (the suspected 'mastermind' behind the blasts who was later murdered), allegedly planted a bomb on Samjhauta Express.

The Indore resident's name has cropped up in Ajmer blasts and Mecca Masjid blasts of Hyderabad. He was arrested on June 17, 2010 for the Ajmer blasts and on June 18, 2011 for Samjhauta blasts where the probe agency alleged that he was also one of the suspects who planted the bomb.

NIA has been given charge of terror cases which include Malegaon 2006 and 2008, Ajmer (Rajasthan), Samjhauta train blasts and Mecca-Masjid (Hyderabad).