The charges against him, however, weren't dropped until May 1999 after prosecutors decided against a new trial.

The man was released by federal magistrate the following day after prosecutors admitted "significant doubt" that the arrested man was indeed the suspect.

He has said he reached the decision after consulting prosecutors in his office, and has declined to elaborate on it.

The men all pleaded not guilty, and several were released on their own recognizance, in some cases after prosecutors made allowances for their age.

On 5 April, four of them were released after prosecutors found insufficient evidence to detain them.

The break was the second apparently caused by illness, and judges ordered a medical examination of the former Yugoslav president after prosecutors expressed skepticism last week.

The charges were dropped in August 2009 after prosecutors determined there was insufficient evidence in the case.

Mr. Williams's name was released after prosecutors obtained a court's permission on the ground that he was a public health threat.

The Justice Department joined the case after prosecutors reviewed the evidence.

The previous trial ended in a mistrial in January after prosecutors charged there had been jury tampering.