REDWOOD CITY, Calif. – In a sign of possible discord in the jury room, the judge in Scott Peterson’s murder case lectured the panel yesterday about the importance of deliberating with an open mind.

“Do not hesitate to change your opinion for the purpose of reaching a verdict if you can do so,” Judge Alfred Delucchi said after summoning jurors to the courtroom just an hour and half after they resumed deliberations.

“The attitude and conduct of jurors at all times is very important,” he added. “It is rarely helpful for a juror at the beginning of deliberations to express an emphatic opinion on the case.”

The jurors listened with serious, even grim expressions before they were sent back into the jury room to deliberate. It was not immediately clear what led to the judge’s instructions, but trial observers speculated jurors are beginning to reach a deadlock.

“They’re stuck,” said Jim Hammer, a former prosecutor and trial regular. The judge “clearly has indications that they’re beginning to hang.”

Jurors, before retiring for the day, later asked to review numerous pieces of evidence, including an anchor found on Mr. Peterson’s boat that prosecutors allege is similar to the ones he used to sink his wife’s body, and transcripts and recordings of telephone calls between Mr. Peterson and his mistress, Amber Frey.

Jurors also requested information on a life insurance policy on Laci Peterson; a fishing license Mr. Peterson bought on December 23; and a transcript of a police interview regarding Mr. Peterson’s whereabouts the day his wife vanished.

Earlier yesterday, Judge Delucchi denied a defense motion for a mistrial after jurors examined the boat prosecutors claim Mr. Peterson used to dispose of his wife’s body in San Francisco Bay.

Defense lawyer Mark Geragos claimed jurors violated the judge’s orders by doing “a juror experiment” when several panelists got inside the boat and rocked it from side to side.

The defense has argued that it would have been nearly impossible for Mr. Peterson to have heaved his wife’s 153-pound body over the edge of the boat without tipping.

As an alternative to a mistrial, Mr. Geragos asked the judge to show jurors a videotaped experiment performed by the defense apparently showing that the boat would have tipped. Judge Delucchi denied the motion.

Mr. Peterson is charged with two counts of murder in the deaths of his wife, Laci, and the fetus she carried. Prosecutors claim Mr. Peterson killed Laci around December 24, 2002, then sunk her weighted body in the bay.

Defense lawyers claim someone else abducted Laci and killed her, then framed her husband.

The sequestered jury began deliberations last Wednesday and recessed for the weekend. Jurors were monitored in a hotel where they could watch only sports and movies on television, and could use a computer without access to the Internet. They were forbidden from discussing the case.

Also yesterday, the presiding judge of the courthouse ruled against media attorneys who were seeking to have cameras stationed about 40 feet down a hallway from the courtroom.