Jurors in the Scott Peterson (search) murder trial got an early start on their weekend when the judge delayed cross-examination of the prosecution's star witness, then sent them home because of what he described as a "potential development."

Judge Alfred A. Delucchi (search) stopped the trial Wednesday just as Amber Frey (search), Peterson's former mistress, was set to be questioned by defense attorney Mark Geragos (search).

"There's been a potential development in this case that has to be checked out before we can go any further," Delucchi told jurors.

Delucchi didn't say what the development was and lawyers are barred by a gag order from discussing it.

The delay came as a surprise even to Frey's attorney, Gloria Allred (search), who said outside court that her client was prepared to testify.

"It is of course frustrating to Amber because she was ready," Allred said. "The delay causes even more of an inconvenience for her and her family ... Amber has suffered such enormous invasions of privacy."

Even Peterson's lawyers appeared to be prepared to move forward with Frey's cross-examination. The courtroom was full of attorneys' friends and family members who had come from as far away as Los Angeles.

Delucchi later canceled Thursday's session without explanation. Court is back in session Monday.

Jurors have heard 24 of hundreds of calls recorded between Peterson and Frey as authorities searched for his pregnant wife, Laci, between late December 2002 and February 2003. Authorities hope to show jurors the affair was Peterson's motive for killing his wife.

Peterson is acccused of killing Laci in their Modesto home on or around Dec. 24, 2002, then dumping her weighted body from a small boat into San Francisco Bay. The remains of Laci and the couple's fetus washed up along a bay shore in April 2003, not far from where Peterson said he launched a solo fishing trip the day he reported her missing on that Christmas Eve.

The defense claims Peterson was framed after the real killer learned of his widely publicized alibi.