Wen Ho Lee was kept in leg irons

Until mid-September Dr Lee faced 59 charges relating to spying for the Chinese government.

He was accused of transferring secret material to unsecured computer tapes - some of which have disappeared.

But Dr Lee was freed from prison after pleading guilty to just one charge.

At the time of Dr Lee's arrest, the prosecuting authorities suggested he had stolen the 'crown jewels' of America's nuclear weapons programme.

But by the time of his release the FBI and the Justice Department were on the defensive, under attack from the presiding judge, Asian American leaders and even President Bill Clinton.

Electrocution threats

But Louis Freeh, the FBI's Director plans an aggressive defence in hearings before Senate committees. He is expected to tell Senators that every one of the charges could have been proved.

And he will deny that the prosecution had anything to do with Dr Lee's ethnicity - the scientist was born in Taiwan.

He will also defend the much-criticised policy of keeping Dr Lee in solitary confinement. Mr Freeh says he was unaware that Dr Lee was kept in leg irons, or that a light was constantly kept burning in his cell.

However it is thought the Bureau's director will admit that FBI agents went too far when they threatened to electrocute Dr Lee.