Saying that 'very serious crimes' with which Pakistan born terror suspect Tahawwur Hussain Rana is charged give him a motive to flee, a US court has again turned down his bail plea.

'Defendant Rana's motion to revoke Magistrate Judge Nan Nolan's detention order is denied,' Judge Harry Leinenweber of US District Court, Northern District of Illinois ruled Wednesday.

Rana, a Canadian citizen living in Chicago, has been accused of helping Pakistan-based terror outfit Lashkar-e-Taiba (LeT) in plotting terror attacks in India including the Nov 26, 2008 Mumbai terror attacks.

He has made several pleas to be released on bond since his arrest last October contending that he was 'duped' by co-accused American-Pakistani LeT operative David Coleman Headley.

Headley, 49, and Rana, 48, were arrested by FBI in October last year on charges of aiding and supporting a terror organisation for attacks against India and a Danish newspaper.

'The evidence in the form of recorded conversations, while not conclusive, appears to corroborate the government's contention that he was a knowing ally of Headley and had been acquainted in advance of the Mumbai attacks,' the US court said.

In addition, the more serious charges if proved would undoubtedly lead to a higher sentence, the court said, adding that Rana has not 'rebutted the presumptions'.

Rana has been indicted of 'very serious crimes which is sufficient itself to trigger probable cause of his guilt which establishes the reputable presumption of a danger to the community'.