As Scott Peterson's (search) double-murder trial enters its second month, many courtroom observers say the prosecution's case appears to be faltering.

Defense attorney Mark Geragos (search) has used prosecution witnesses to bolster his argument that authorities conducted a shoddy investigation before charging Peterson with killing his pregnant wife.

Geragos was scheduled to resume his cross-examination Monday of Detective Allen Brocchini, the first investigator assigned to the report that Laci Peterson (search) had vanished. Last week, Geragos got Brocchini to admit to several investigative lapses.

"It's still a horse race. It's just not a close one right now," said former Alameda County prosecutor Michael Cardoza, now a practicing criminal defense lawyer.

Peterson, 31, is accused of murdering his pregnant wife on or around Dec. 24, 2002, then sinking her body in San Francisco Bay (search). Defense lawyers say he was fishing on the bay when Laci Peterson disappeared, and that someone else must have abducted her near their Modesto home, then framed Peterson after hearing his well-publicized alibi.

Over two days of questioning last week, Geragos cornered Brocchini on several details of the investigation, including:

— That police didn't fully exhaust the lead that a witness reported seeing a pregnant woman walking a golden retriever, the same kind of dog the Petersons had, on Dec. 24. Brocchini said the witness couldn't positively identify the pregnant woman as Laci Peterson.

— That Brocchini's report didn't include a police interview with a woman who saw Laci Peterson at the warehouse where her husband stored his small boat. Prosecutors have insisted that Peterson hid the boat as part of his plan. Attorneys in the case have been barred from speaking with reporters about the case, but police say other police reports include the woman's recollection.

— That Brocchini didn't know of two witnesses who reported seeing Laci Peterson walk the couple's dog the day before she vanished. Prosecutors have questioned Peterson's story by asserting his wife stopped exercising weeks prior because of pregnancy-related dizziness.

Geragos also got Brocchini to suggest innocent explanations for several pieces of evidence that other Modesto policemen concluded could be part of Peterson's attempts to clean up a murder scene at his home, such as a pile of dirty towels on a washing machine.

Cardoza, who has watched most of the trial firsthand, said it appears authorities rushed to arrest Peterson last year before they had built more than a circumstantial case.

"Unless there's really some smoking gun somewhere, they're going to be awfully sorry they filed this case," Cardoza said.

Even some attorneys who believe prosecutors have enough evidence to convict Peterson find fault with their execution.

"The pieces of it are all there. The trouble is with the prosecution's presentation," said Dean Johnson, a former San Mateo County prosecutor and now a criminal defense attorney.

Johnson said prosecutors need to weave their story more tightly for jurors, and noted that with the trial expected to last several months more, they have time to recover.

"Yogi Berra (search) said, 'It ain't over 'til it's over,'" he said, "and that is particularly true in circumstantial cases like this because the only way you can tell who wins the case is when all of the evidence is in and you put together the pieces."

A juror who was dismissed last week held a dimmer view of the prosecution's case.

"There's no way that you could possibly convict him," Justin Falconer said. "He'd be innocent, because the prosecution hasn't given us any reason to believe otherwise."

Falconer was removed days after a television news crew videotaped him briefly chatting with Laci Peterson's brother as the two passed through a courthouse metal detector. Falconer said the judge told him he had become a distraction.

Falconer said that though Stanislaus County Deputy District Attorney Joseph "Rick" Distaso is outmatched by Geragos, he insists on using witnesses to reiterate the same minor details.