John Dodd, the lawyer working on behalf of the fund manager implicated in what is the largest ever insider trading operation, made a filing to the court claiming that the improper methods were used to gain the evidence.
The evidence equates to over 2,400 conversations Mr Rajaratnam had with more than 130 people, including family, friends and colleagues.
In the filing Mr Dodd was quoted by Bloomberg as saying: âIn its zeal to break new ground and in an effort to salvage its nine-year pursuit of Mr Rajaratnam, the government violated its obligation of candor and forthrightness to the court.
âThe government obtained the courtâs authorisation to use wiretaps based on the sworn affidavit of an FBI agent that was rife with âdeliberately or recklesslyâ false statements.â
Mr Rajaratnam is the central figure in a case which has seen more than 20 people charged.
The group is alleged to have made more than $50 million worth of illicit profits via insider deals.
By Jim Ottewill