Scott Peterson's (search) defense attorneys have appealed a judge's order that lets the public attend the hearing at which prosecutors will lay out their evidence against the man charged with killing his wife and unborn child.

"Unless this court intervenes and closes the preliminary hearing, there will be no chance of obtaining an unbiased jury," defense attorney Mark Geragos (search) wrote in a request filed Wednesday.

Judge Al Girolami (search) ruled last week that the hearing would remain open, though he later banned all cameras and recording devices.

Geragos wants the state appeals court to overturn Girolami — or order another hearing at which the judge would explain how his decision is not in "direct conflict" with prior rulings that sealed most documents and imposed a gag order.

Peterson's preliminary hearing is set for Sept. 9. At such hearings, a judge decides whether the case should go to trial after hearing testimony from witnesses.

Geragos was surprised by the judge's ruling this week to ban cameras from the courtroom after earlier ruling against defense motions to close the hearing.

"It sounds like he repeated everything I said in my arguments to close the hearing," he said.

Peterson, 30, has pleaded innocent to two murder charges in the deaths of his wife, Laci, and the couple's unborn child. Laci Peterson (search), 27, was eight months pregnant when she disappeared Christmas Eve; her body and that of her son washed ashore along San Francisco Bay in April.