Tamang was arrested on August 16 and kept in CID custody at Pintal village near here after he was produced in Darjeeling district court the next day, Superintendent of Police, Darjeeling, Debendra Pratap Singh said.
Tamang escaped on the pretext of going to toilet this morning, he added.
Search operations had been launched to nab the fugitive, he said, adding nobody had been suspended in this connection as yet.
Madan Tamang was murdered on May 21 while supervising arrangements for a meeting of the All India Gorkha League at Darjeeling town.
Published 22 August 2010, 05:52 IST