Kunhimohammed was among the four most wanted and had been absconding for the last 16 years, they said.
He was nabbed at Panangankara in Malappuram after a CB-CID Special Investigation Division team rushed to the town on receiving a tip off, police said.
He had reportedly supplied explosive material and also given asylum to some of the accused in the blast cases.
Kunhimohammed would be brought to the city later and produced in court, they said.