A juror in Scott Peterson's (search) double-murder trial was dismissed and replaced Tuesday, forcing the jury to start its deliberations all over again.

The pool of 12 had been mulling over the case for five days. Juror No. 7 was let go by Judge Alfred A. Delucchi (search) on Tuesday and replaced by an alternate juror, a white woman in her 30s who's the mother of four boys, FOX News has learned.

It wasn't immediately clear what the errant juror, said to be an Asian woman in her 50s or 60s and a retired Pacific Gas & Electric Co. (search) employee, did to warrant being booted out of court.

A source told The Associated Press on condition of anonymity that she had apparently disobeyed the judge's orders to consider only the evidence presented at the trial.

"You must decide all questions of fact in this case from the evidence received in this trial and not from any other resource," Delucchi told the panel after replacing the juror with an alternate. "The people and the defendant have the right to a verdict reached only after full participation."

The decision came just hours after the jury was called together for a special hearing Tuesday morning because it appeared one member may have done research during deliberations, which could have led to a mistrial.

"We're going to send you back. Start all over again and keep in touch," Delucchi told the panel.

The juror who was sent home was said to have been emotionless during testimony and seemed responsive to defense lawyer Mark Geragos, FOX has learned. She reportedly said she could believe Peterson was falsely accused during jury selection, sources told FOX News.

"I don't see a motive for something that heinous," Juror No. 7 apparently said before the trial began, though she acknowledged prosecutors could be "keeping the case close to the vest."

The dismissed juror remains under a court-imposed gag order, the judge reminded her. She is the second juror dismissed from the case; the first came early in the proceedings.

The alternate replacing juror No. 7 is nicknamed "Pinky" and "Strawberry Shortcake" because her hair has been dyed pink or bright red and she has a penchant for pink clothing. The tattooed mother has reportedly been expressive during testimony, crying on several occasions — including over the exhibit of autopsy photographs.

The replacement juror worked at a bank, and has a brother who was in and out of prison for drugs — leading her mother to become a drug counselor at a methadone clinic.

Whether the juror switch means anything when it comes to deciding if Peterson is guilty of murder remains to be seen. Also unclear is whether the other 11 members of the six-man, six-woman jury will be able to follow the judge's orders and set aside any conclusions made during the first five days of deliberations.

Peterson, 32, is charged with two counts of murder in the deaths of his wife, Laci, and the fetus she carried. Prosecutors claim Peterson killed Laci around Christmas Eve 2002, then dumped her weighted body from his boat into San Francisco Bay.

The jury has two choices should they decide to convict Peterson — first- or second-degree murder. A first-degree conviction would mean jurors believe Peterson planned the killings in advance, and it could carry the death penalty or life without parole.

Deliberations began last week after five months of testimony.

On Tuesday morning, at the start of its fifth day of deliberations, the jury was called to chambers by Delucchi, though it was unclear whether the deliberations were put on hold during the meeting. The judge didn't say why he summoned lawyers to meet with him privately.

But sources inside the courtroom told FOX that the judge was interrogating the jury to determine whether the allegation that one of them had done research was true — and if so, what the nature of that outside work was.

If the research in question was legal research that had been shared with the entire jury pool, then the jury could have been tainted and a mistrial declared. That didn't ultimately happen, however.

Jurors are forbidden from doing outside research of any kind that relates to the trial they are deciding.

If a mistrial had been declared it would mean a whole new trial, starting with the selection of a new jury. As it is, the dismissal of No. 7 means the jury must scrap everything it's done, choose a new foreman and begin deliberations anew.

The allegation of possible outside research by one of the jurors came a day after the panel appeared to hit a snag, prompting Delucchi to summon the jury to the courtroom during Monday's deliberations.

It was impossible for anyone outside the jury room and the judge's chambers to know immediately whether the dismissed juror was the one the judge was referring to Monday when he lectured the panel about the importance of keeping an open mind, but lawyers for both sides left the courtroom smiling.

Monday's lecture came after the jury indicated that the panel was deeply divided and unable to reach a consensus on the murder charges. "It is rarely helpful for a juror at the beginning of deliberations to express an emphatic opinion on the case," the judge said before sending the panel back to the jury room on Monday.

Judging from her statements during jury selection and her demeanor throughout the trial, Dean Johnson, a former San Mateo County prosecutor who has been closely watching the case, felt she would be sympathetic to the defense. "And now she's gone after apparently doing individual research to bolster whatever opinions she had," he said.

Her replacement, on the other hand, seems so emotionally involved in the case that it might be difficult for her to separate her feelings from the facts, Johnson said. "She's not going to be able to take her emotions out of the equation here."

Daniel Horwitz, a criminal defense attorney who also has watched the trial, said the replacement bodes well for the defense, calling her "a woman who will not immediately join the group. She's clearly a non-conformist." Any jurors leaning toward a conviction would likely be frustrated by her, he said.

After hearing from the judge on Monday, jurors asked to review numerous pieces of evidence, including San Francisco Bay tidal charts seized from Peterson's computers; an anchor found on Peterson's boat that prosecutors allege is similar to the ones he used to sink his wife's body; transcripts and recordings of telephone calls between Peterson and his mistress, Amber Frey (search); information regarding a life insurance policy on Laci Peterson (search); a two-day fishing license Peterson purchased on Dec. 23 for what he claimed was a last-minute Christmas Eve fishing trip; and a transcript of a police interview of Peterson regarding his whereabouts on the day his wife vanished.

Jurors earlier had viewed the small aluminum boat prosecutors claim Peterson used to dispose of his wife's body. The remains of Laci and the fetus were discovered a few miles from where Peterson claims to have gone fishing alone the day his wife vanished.

After the boat viewing, defense lawyer Geragos sought a mistrial, claiming jurors violated the judge's order by doing "a juror experiment" when several of the panelists got inside the boat and rocked it from side to side. The judge quickly denied the motion.

As an alternative to a mistrial, Geragos asked the judge to be allowed to show jurors a videotaped experiment performed by the defense. Delucchi denied that request as well.

Defense lawyers have argued that it would have been nearly impossible for Peterson to have heaved his wife's 153-pound body over the edge of the boat without tipping.

Geragos did a videotaped experiment apparently showing the boat would have tipped, but Delucchi ruled against allowing him to show the video to jurors during the trial.

FOX News' Catherine Donaldson-Evans, Rita Cosby, Trace Gallagher, Lis Wiehl, Greta Van Susteren and The Associated Press contributed to this report.