The lawyers asked U.S. District Judge Ronald L. Buckwalter to question the juror and other members of the panel.
"An immediate suspension of deliberations and a delicate but probing judicial inquiry is warranted," lawyers NiaLena Caravasos and Peter Goldberger stated in the petition. "Depending on the results of that inquiry, it seems that one or more jurors ought to be removed and possibly replaced . . . or that a mistrial will be required."
Assistant U.S. Attorneys Robert A. Zauzmer and John J. Pease declined to comment on the filing, which is expected to be the focus of a hearing tomorrow morning.
The document outlined several remarks made by the juror on Facebook, a social-networking Web site, and Twitter, a micro-blogging site that allows postings of up to 140 words.
It was unclear how the defense had learned of the postings.
On one posting March 5, the first day of deliberations, the juror sent a text message via Twitter stating that "Day 1 has come to a close," the defense petition stated. After the second day of deliberations, the juror posted a "status" report on Facebook, stating that "today was much better than expected and tomorrow looks promising too!"
On Friday, the defense contended, the juror sent a text message on Twitter: "This is it . . . no looking back now."
And later that night, Goldberger and Caravasos stated, the juror wrote on Facebook: "Stay tuned for a big announcement on Monday everyone!"
The jurors, 10 women and two men who have not been sequestered, are from Philadelphia, Bucks, Montgomery, Lehigh, and Northampton Counties. They began deliberating after more than four months of testimony.
Three alternates who sat through the trial have remained on standby in case any of the jurors cannot continue. If an alternate is seated on the jury, deliberations will have to begin anew.
Fumo, 65, a once-powerful Democrat in Harrisburg and Philadelphia, is charged in a 137-count indictment with obstructing justice and defrauding the Senate and two nonprofits, the Independence Seaport Museum and Citizens' Alliance for Better Neighborhoods.
His codefendant, Ruth Arnao, 52, the former head of Citizens' Alliance, is charged in 45 counts with obstructing justice and in the alleged fraud of Citizens' Alliance.
Fumo's lead defense attorney, Dennis J. Cogan, declined to comment on the petition. The filing said it contained only information that is publicly visible on the Internet.
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