The sister-in-law of Scott Peterson, who was convicted in the death of his pregnant wife and unborn son nearly two decades ago, said evidence she has collected over the years shows there's "no scenario of guilt" for him. 

Janey Peterson told CBS News' "48 Hours" in an episode that aired Saturday night that investigators failed to follow up on leads in the murder of Laci Peterson and Connor, the couple's unborn child. Laci Peterson disappeared from her Modesto, California, home on Christmas Eve 2002 while eight months pregnant. 

Peterson was arrested after Amber Frey, a massage therapist living in Fresno, told police that they began dating a month before his wife’s death and that he had told her she was dead.

Prosecutors said Peterson dumped his wife's body in San Francisco Bay and he was sentenced in 2005 to death. He has maintained his innocence and is preparing for a new sentencing trial.

SCOTT PETERSON FAMILY REACTS TO HIS CASE BEING RECONSIDERED BY CALIFORNIA SUPREME COURT

Janey Peterson said she created a "war room" detailing every aspect of the case. 

"There's no scenario of guilt for Scott," she told "48 Hours." "He's on death row for the murder of his wife and child and no one has ever said what time he did this crime, how he did this crime or the series of events of how he carried out this crime."

She maintains the Modesto Police Department didn't follow up on leads regarding a home burglary that occurred across the street from the Peterson residence. The incident involved five people but only resulted in police interviews with two suspects, she said. 

Janey Peterson theorized that Laci caught the burglars in the act and she was kidnapped and killed as a result. She alleged that neighbors saw Laci Peterson the morning she disappeared, after her husband had already left their home for a fishing trip. 

"There is no series of circumstances that fits the evidence where he could possibly have done it," she said over Zoom in her brother-in-law’s appeal hearing last week, according to KOVR-TV. "The justice system has failed here, and a lot of aspects have failed. And it started with the Modesto Police Department. And it started with the fact that they didn’t follow up on evidence that showed Laci was alive the morning of Dec. 24."

She said a corrections officer at a California prison called Modesto police saying an inmate was overheard discussing the kidnapping and murder of Laci Peterson after she witnessed the burglary. Authorities said the burglary occurred two days after Peterson disappeared, KOVR reported. 

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Jon Buehler, one of the original detectives in the case, said no evidence has surfaced to make him think anyone other than Scott Peterson was responsible for the murders. 

 "Well, I guess it's possible," he said. "But you know, there's still people that believe the earth is flat, too."