The evidence against Scott Peterson was entirely circumstantial. No witness saw him kill his pregnant wife Laci, and no confession or direct forensic link tied him to her death. Instead, prosecutors stacked dozens of interlocking facts: a suspicious alibi, a secretly purchased fishing boat, cement residue suggesting homemade anchors, an ongoing affair with Amber Frey captured on more than 300 recorded phone calls, Laci’s and their unborn son Conner’s bodies washing ashore within a few miles of the spot where Scott claimed to have been fishing on Christmas Eve 2002, GPS-tracked returns to that same marina, and an attempted trip toward the Mexican border with cash, a changed appearance, and his brother’s driver’s license. On November 12, 2004, after seven days of deliberation, a jury convicted him of first-degree murder for Laci and second-degree murder for Conner.
The Christmas Eve Alibi and the Secret Boat
Laci Peterson was eight months pregnant when Scott reported her missing on Christmas Eve 2002. He told police he had left their Modesto, California, home that morning to fish alone at the Berkeley Marina, roughly 90 miles away, and returned that afternoon to find her gone. He told Laci’s stepfather, Ron Grantski, that he had originally planned to golf and switched to fishing because of the cold. Other people got a different version. Small inconsistency, immediate suspicion.
The bigger problem was the boat itself. A detective testified at the preliminary hearing that Scott had bought a fishing boat on December 9, 2002, two weeks before Laci vanished, paying with fourteen $100 bills. He hadn’t told family or friends about it. For a man describing fishing as a last-minute decision, a secretly purchased boat kept in a rented warehouse read as premeditation.
Cement Residue and Homemade Anchors
Inside the warehouse where Scott kept the boat, investigators found cement residue on the trailer, on Scott’s pickup truck, and on the warehouse floor. A single homemade cement anchor sat inside the warehouse. Prosecutors argued Scott had made multiple anchors and used the missing ones to weigh Laci’s body down in San Francisco Bay. One remained; the others, they said, went into the water with her. No additional anchors were ever recovered from the bay, so the argument rested on the traces of production and the conspicuous absence of the finished pieces.
The boat was a small aluminum craft, easily launched by one person from the Berkeley Marina ramp. That fact carried its own weight for the prosecution: no partner, no witnesses, no help needed.
Amber Frey and 300 Recorded Phone Calls
Scott had been carrying on an affair with Amber Frey, a massage therapist from Fresno, since November 20, 2002. He saw her several times in early December. On December 6, more than two weeks before Laci disappeared, Scott told a mutual friend that he had “lost his wife.” On December 9, he told Amber he “had been married,” using the past tense. His wife was alive and eight months pregnant.
After Laci vanished on December 24, Scott kept calling Amber as though nothing had changed. On New Year’s Eve he told her he was celebrating in Paris. He was in Modesto. Amber learned from a friend in law enforcement on December 30 that Scott was the husband of the missing woman in the news, and she contacted the Modesto Police Department. Officers fitted her with recording equipment.
Police captured more than 300 calls between them. The tapes played for the jury caught Scott claiming to be in Europe and Maine when he was in Modesto, sometimes helping with the search for his own wife. In one call he told Amber, “The media has been telling everyone that I had something to do with her disappearance. So the past two weeks I’ve been hunted by the media.” When she asked what would happen if Laci were found dead, he replied, “My God, don’t say that,” then, “All our questions are answered and then we can find the bastards that did it.”
The affair did two jobs for the prosecution. It supplied a motive — a man who wanted out of marriage and impending fatherhood — and it demonstrated a sustained capacity for calculated lying to the people closest to him.
The Bodies Washed Ashore Near His Alibi Location
In April 2003, roughly four months after Laci disappeared, both victims washed ashore on the eastern edge of San Francisco Bay. On April 13, an infant’s body was found in marshy grassland about a mile north of the Point Isabel Regional Shoreline near Richmond. The next day, Laci’s decomposed torso washed ashore near Point Isabel itself. The two locations were roughly a mile apart.
The geography did most of the work. Out of every stretch of coastline within reach of Modesto, Laci and Conner surfaced within a few miles of the exact spot where Scott had placed himself on the morning she vanished. Prosecutors did not need to prove the mechanism. The coincidence carried the point.
Forensic Evidence and Its Limits
Investigators found a single strand of dark hair wrapped around a pair of pliers inside Scott’s boat. The FBI crime lab performed mitochondrial DNA analysis and found the hair matched a sample from Laci’s mother, Sharon Rocha. Because mitochondrial DNA passes from mother to child, the match was consistent with the hair belonging to Laci.
This piece had honest limitations, and the defense pressed them. Mitochondrial DNA cannot identify a single person the way nuclear DNA can. The judge told the jury the profile could statistically be found in roughly one out of every 112 white individuals. Consistent with Laci, but not a fingerprint. A police K-9 unit also picked up Laci’s scent at the Berkeley Marina boat ramp, supporting the theory that her body had been transported there. Each forensic finding was weak on its own; together with the rest of the case, they reinforced a coherent picture.
GPS Tracking Showed Him Returning to the Marina
Police placed GPS tracking devices on Scott’s truck after Laci disappeared. Investigators physically followed him to the Berkeley Marina three times in early January 2003. After they ended in-person surveillance on January 11, believing Scott had spotted them, the GPS recorded him returning to the marina at least five more times that month.
Prosecutors framed the pattern plainly: a killer returning to the scene. A grieving husband who had happened to fish there on December 24 would have no reason to keep going back, especially with the area under active search. The defense pointed out that Scott also drove to other locations around the Bay Area, but the repeated, targeted returns to the specific stretch of water where he claimed to have been fishing carried obvious weight.
The Arrest Near the Mexican Border
Scott’s behavior between the disappearance and the arrest went beyond shifting statements. He put the Modesto house on the market. He looked into selling Laci’s car. Family members described his demeanor during the search as strangely calm.
When the bodies were identified in April 2003, police arrested him in San Diego, roughly 30 miles from the Mexican border. He had dyed his normally dark hair and grown a goatee. Inside his car, officers found approximately $10,000 to $15,000 in cash, his brother’s driver’s license, multiple cell phones, a rope, knives, camping gear, and a shovel. Prosecutors called it flight preparation and consciousness of guilt. The changed appearance, the cash, and the border proximity were difficult to explain as a road trip.
What the Defense Argued
Defense attorney Mark Geragos offered alternatives. He suggested Laci had been abducted, possibly by people connected to a burglary that occurred across the street from the Peterson home the same day she disappeared. He also proposed that whoever actually killed Laci could have dumped her body in the bay after hearing news of Scott’s fishing alibi, deliberately framing him.
Defense witnesses tried to shift the timeline, including a neighbor who said she found the Petersons’ dog loose on the street mid-morning on December 24. Geragos attacked the prosecution’s bay-current analysis and argued the separate points where the two bodies washed up were consistent with someone else disposing of them later. None of the alternative theories opened enough space for reasonable doubt against the weight of Scott’s lies, the secret boat, the cement traces, and the location where the bodies were found.
Where the Case Stands Now
The jury returned first-degree murder on Laci and second-degree murder on Conner, and Peterson was originally sentenced to death. In August 2020, the California Supreme Court upheld the murder convictions but overturned the death sentence, finding the trial judge had improperly dismissed prospective jurors who expressed general opposition to capital punishment without asking whether they could still be fair at the guilt phase. Rather than retry the penalty phase, the Stanislaus County District Attorney’s Office agreed to resentencing, and in December 2021 Peterson was resentenced to life without the possibility of parole.
Peterson’s defense has also raised juror-misconduct claims involving Juror No. 7, Richelle Nice, alleging she failed to disclose during jury selection that she had been a victim of domestic violence. The courts have examined the claims, and they have not resulted in a new trial.
In January 2024, the Los Angeles Innocence Project took up the case. It has argued the jury never heard evidence that could have changed the outcome, including material tied to the burglary across the street from the Peterson home. Prosecutors have maintained the burglary was unrelated. In May 2024, a judge granted DNA testing on a 15.5-inch strip of duct tape found on Laci’s clothing when her body was recovered, and denied testing on 13 other items the defense requested. In August 2025, the Innocence Project filed a habeas corpus petition in San Mateo County Superior Court. Peterson continues to maintain his innocence.