Updated

Laci Peterson's friends and family swarmed to her home the night she was reported missing, frantically scouring the neighborhood for clues as to what happened to the woman who was eight months pregnant.

The sad truth would come out months later when the bodies of Laci Peterson (search) and her fetus washed ashore along San Francisco Bay.

Her half-sister, Amy Rocha, spent a portion of Thursday testifying for the prosecution against Laci Peterson's husband, Scott, who is charged with the murders. She described the scene at the Petersons' home on the day Laci Peterson vanished -- Christmas Eve 2002 -- and discussed the first phone call she received from Scott Peterson (search) at about 5:15 p.m.

"He was panicked," Rocha said.

She didn't recall much else from that evening, she said, mostly that "everybody was pretty frantic" and that a steady stream of police and friends arrived to begin the search.

"I just remember more people coming and there are a lot of police there," Rocha said. "The next thing I remember was going house to house with a picture of Laci."

Rocha is set to return to the witness stand Monday.

The questioning capped the first full day of testimony in the case that is expected to last up to six months.

In an attempt to establish when Laci Peterson died, prosecutors focused on the clothing she wore during the last day that anyone besides her husband -- and alleged killer -- reported seeing her alive.

Meanwhile, defense lawyers assailed what they characterize as a botched investigation that culminated in two murder charges against Scott Peterson.

Prosecutors claim Peterson killed his wife in their Modesto home on or around Christmas Eve morning 2002, then drove her body to San Francisco Bay and dumped it from his small boat. Lawyers for Peterson, who says he was fishing on the bay that day, speculate that someone else abducted his wife and then framed him after learning his alibi.

The remains of Laci Peterson and her fetus were badly decomposed when they washed ashore in April 2003, and authorities have not offered physical evidence to pinpoint exactly how or when they were killed.

As a result, Distaso spent much of Thursday talking about her clothing.

Peterson told police that his wife wore a white shirt and black stretch pants when he left for a solo fishing trip Christmas Eve morning. Prosecutors have said her remains were clad in khaki pants.

Two prosecution witnesses who work at a spa Laci Peterson visited around midday Dec. 23 testified she wore a white shirt and black stretch pants. Two other witnesses, including Laci Peterson's half-sister, testified she was wearing light-colored pants that evening at a salon.

That chain of recollections could fit the prosecution's theory that Peterson killed his wife late Dec. 23 or early Dec. 24 -- after she had changed clothes -- then disposed of the body after daybreak.

Peterson, 31, would face the death penalty or life without parole if convicted.

Even as prosecutors tried to make their case, Peterson's attorneys tweaked authorities with assertions of their incompetence.

The owner of Sweet Serenity Day Spa, where Laci Peterson went for a waxing treatment just after noon Dec. 23, said police inaccurately recorded parts of her initial statement. Michelle Buer said she didn't tell authorities on the day Laci Peterson vanished that she suspected Scott Peterson was involved -- though she did say that later.

Defense lawyer Mark Geragos (search) pointed out that although video surveillance tapes were available from the salon where Laci Peterson accompanied her husband for an hourlong haircut that evening, police didn't try to retrieve them until after store workers had taped over the content.

Police do not have any pictures or video showing what Laci Peterson wore on a day she went grocery shopping, visited the spa and salon and made sure the house was clean. The errands appeared to be routine preparations for hosting a Christmas dinner with her family.

Rocha also testified her half-sister Laci hadn't been feeling well -- that she became sick when she walked and was often dizzy and nauseous.

Peterson told police his wife was preparing to walk their dog when he left for his fishing trip. Prosecutors have said that is just another lie, adding that Laci Peterson stopped walking her dog weeks before at her doctor's request.