It is a rare case where a convict undergoing a life sentence is the "most credible" witness of a probe agency against a person who has been a public representative for the past 28 years, jailed Nationalist Congress Party (NCP) leader Nawab Malik's lawyer told a special court here on Friday.

Malik, a former Maharashtra minister who is currently in judicial custody, was arrested on February 23 under the Prevention of Money Laundering Act (PMLA) by the Enforcement Directorate (ED) in a probe linked to the activities of fugitive gangster Dawood Ibrahim and his aides.