Talansky is one of two pivotal witnesses in the investigation that alleges that Olmert unlawfully received millions of shekels in illegal campaign funding over a period of 15 years.

A jailhouse informer was the pivotal witness against Ms. Durante and the linchpin of the case.

Ms. Gonzalez is the pivotal witness against Mr. Trantino.

Mr. Huang has for years seemed like a pivotal witness who could jump-start the Justice Department's criminal investigation and answer many unanswered questions that have swirled around the campaign finance investigations.

She was introduced as a "pivotal witness" in the Brownstone Murder Mystery storyline arc.

In 1989, Thorson emerged as a pivotal witness in the prosecution of gangster Eddie Nash in the 1981 quadruple murders of the Wonderland Gang.

Mr. McElroy, 45, who is serving a Federal sentence for racketeering, murder and loan sharking, is the prosecution's pivotal witness.

The decision was particularly surprising considering the number of guilty pleas and the fact that a major architect of the arrangement scheme was the government's pivotal witness.

There is little question that Mr. Brown was the case's pivotal witness.

The pivotal witness against Mr. Malik was a former employee of his whose identity is protected by a court order.