DA: Peterson Alibis Inconsistent

California prosecutors hope to prove beyond a reasonable doubt that Scott Peterson killed his pregnant wife Laci and their unborn son.

In the first 10 minutes of his opening statement, assistant district attorney Rick Distaso tried to show inconsistencies in Scott Peterson's alibi, reports CBS News Correspondent Steve Futterman. According to Distaso, Peterson told neighbors he had been golfing, told Laci's mother he had been fishing, then told an uncle he had been golfing. Where he was when Laci disappeared is a key element in the case.

Nearly a year-and-a-half after eight-months-pregnant Laci Peterson disappeared, after a one melodramatic twist after another, the trial of husband Scott Peterson for the murder of his wife and unborn son was getting under way in a Redwood City, Calif., courtroom.

Peterson claims someone else abducted his wife and eventually murdered her — even though it was subsequently revealed that he was having an affair with another woman and had been found trying to cross into Mexico with a large amount of cash shortly after Laci's disappearance.

Laci Peterson did not turn up until April 2003 - a body floating in the water, with the fetus also found in the water - separate from her own body.

Former fertilizer salesman Scott Peterson, charged with murder in both deaths, had one of the nation's most prominent criminal defense attorneys - Mark Geragos - by his side Tuesday as opening statements begin in the trial.

Jury selection for the trial lasted 12 weeks and the trial is expected to last an additional five months or more. CBS News Correspondent Jennifer Donnelan reports the Peterson jury includes a school coach, a social worker, a former police officer, and a woman whose fiancé was convicted of murdering a stranger two decades ago.

If convicted, Peterson could face the death penalty or life without parole.

It is unclear which witnesses will be called because the list is sealed and attorneys are working under a sweeping gag order. But it is clear that the defense is working to create reasonable doubt in a case that California Attorney General Bill Lockyer early on described as a "slam dunk" for the prosecution.

Some observers now say the outcome is too close to call.

"This case from the beginning has been fraught with problems. The best thing the prosecution has going right now is all the adverse publicity against Peterson," said Los Angeles defense attorney Steve Cron.

Because of the gag order, the public will likely be surprised by a lot of what comes out at trial, Cron added.

"But from what we've seen so far, I don't see this as a slam dunk conviction by any means. I think he (Peterson) has a reasonably good chance of prevailing," Cron said.

Geragos, in fact, recently accused authorities of withholding evidence until just days before the trial that could exonerate Peterson.

In a motion alleging prosecutorial misconduct, the defense attorney claims authorities have known since days after Laci Peterson disappeared just before Christmas 2002, of a witness who saw the woman being shoved into a van by at least two men.

"The witness confirmed his sighting of a woman he identified as Laci and her two abductors," Geragos wrote, saying the account was just recently turned over to the defense.

It is likely Geragos will call the witness, a former reserve police officer, to testify.

There are others, Geragos claims, who also saw a suspicious van in the Petersons' neighborhood around the time Laci Peterson vanished.

Authorities allege Peterson, 31, killed his 27-year-old pregnant wife in their Modesto home because he was having an affair, then drove her body nearly 100 miles to San Francisco Bay and dumped it from his small boat.

The bodies of Laci Peterson and her fetus washed ashore a few miles away from the Berkeley Marina, where Peterson told authorities he set out on a solo fishing trip on the morning of Dec. 24, 2002, the same day he says his wife vanished.

Prosecutors will use many of Peterson's nearly 3,000 telephone conversations that police recorded after his wife's disappearance. Likely among the most damaging, experts say, are calls between Peterson and his mistress, Amber Frey, who began cooperating with authorities soon after Laci Peterson vanished.

Peterson was arrested in April 2003, not far from the Mexican border. He was carrying $10,000 and his brother's driver's license and had dyed his hair blond.

Geragos has floated other theories, such as satanic cult connections, and that the killer could have dumped the bodies in the bay after hearing of Peterson's fishing trip account.

"We are certainly going to hear more detail about the prosecution's theory of the case than we've heard before," says CBS News Legal Analyst Andrew Cohen. "Unless they've hidden their best evidence until now, prosecutors are trying to get a capital conviction against Scott Peterson without having a murder weapon or a specific cause of death. And that's not going to be easy, especially with the good defense attorneys Peterson has."