An attorney for the hotel maid who accused former International Monetary Fund chief Dominique Strauss-Kahn of sexual assault filed a motion Monday asking a judge to halt proceedings in the case and appoint a special prosecutor.

The move comes hours before Nafissatou Diallo and her attorney, Kenneth Thompson, are scheduled to meet with prosecutors. Thompson said Sunday that he believes prosecutors intend to announce at that meeting they will drop charges against Strauss-Kahn.

"We're calling for a special prosecutor to prevent Manhattan District Attorney Cyrus Vance from irreparably damaging Ms. Diallo's right to have her criminal case go to trial, " Thompson said.

The motion cites allegations of "abuse of confidence, unfair treatment and bias and prejudices," by Vance that make him unfit to try the case. Vance's office declined to comment on the motion.