Earlier this week WorldCom Inc's former chief accounting officer Buford Yates pleaded guilty to charges of securities fraud and conspiracy, following a guilty plea by former controller David Myers on Sept 26.

Lawyers said Vinson, Yates and Myers are likely to provide evidence against former top WorldCom executives, possibly including ex-CEO Bernie Ebbers and former chief financial officer Scott Sullivan, in exchange for lenient sentencing in the case.

So far Ebbers has not been charged in the case, while Sullivan has entered a not-guilty plea.

Hadad said a fourth defendant, former WorldCom accountant Troy Norman is scheduled to appear in court later today.

The court spokesman said Vinson is scheduled to be sentenced on Jan 13 and faces a statutory maximum penalty of up to 15 year in prison and up to 1.25 million usd in penalties.

He said Vinson also is potentially liable for "twice the gross gain or loss resulting from the crime," which in this case could represent billions of dollar s, although lawyers said she is unlikely to receive the maximum jail term or financial penalties.