by KYW's Tony Hanson

There has been a major development -- a staggering development for the government -- in the federal prosecution of former Pennsylvania state senator Vince Fumo.

A key cooperating witness might be off the witness list, and the case is in limbo until the attorneys and judge decide what to do next.

Leonard Luchko (in file photo) was expected to testify that he conspired with then state senator Fumo to obstruct justice by deleting emails and other electronic evidence.

But federal prosecutor Robert Zauzmer revealed that the government learned on Friday that Luchko has been communicating with Fumo, his co-defendant Ruth Arnao, and others:

"He has been corresponding by email with the defendants and with witnesses and with other members of the defendants' staff both before and after the trial and before and after his guilty plea."

Authorities say there are thousands of emails and Internet blog comments -- substantive comments that could undermine Luchko's credibility. But the specific substance of the emails and blog comments has not been revealed.

Stay tuned to KYW Newsradio 1060 for updates on this developing story.