EXCLUSIVE: Scott Peterson has filed a new appeal in his 2004 California murder conviction as Fox News has obtained a previously unseen family photo of the 50-year-old sharing a lighthearted moment on a prison conference call.

Peterson received a death sentence nearly 20 years ago after a California jury found him guilty of killing his wife and their unborn son, then dumping them in the San Francisco Bay on Christmas Eve in 2002. They washed up separately months later. 

But his family has maintained his innocence the entire time — and a judge late last year removed him from death row amid allegations of juror bias. While he was resentenced to life without parole in December, the judge declined to grant him a new trial.

The photo, exclusively obtained by Fox News' Laura Ingle, can be seen in a new FOX Nation special, "Reporter's Notebook: The Scott Peterson Case," chronicling two decades of the saga.

KEY QUESTIONS UNANSWERED IN CASE

Scott Peterson call cropped

A still image from a video conference call, zoomed in to isolate Scott Peterson. The background, showing trees and cushions, was digitally inserted by the virtual meeting software, according to family members. He spoke with them from a concrete holding cell. (Janey Peterson)

The photo originated in a May 22, 2022 Webex call, sharing a moment with family members, while he was still in the San Quentin prison.

A virtual backdrop shows a window with tress and a couch with pillows — but he was sitting in a cell wearing his gray T-shirt and prison uniform, according to his sister-in-law, Janey Peterson.

Scott Peterson family conference call

Scott Peterson pictured top right in a conference call from prison, speaking with family members. Relatives shown include his brother Joe Peterson and sister-in-law Janey on the upper left, his sister Susan and her husband Ed Caudillo, and Lee Peterson, his father, in the bottom middle. Caudillo is modeling navy blue coveralls they had just purchased for Lee, in a virtual call from May 22, 2022. (Janey Peterson)

Scott Peterson is pictured top right in a conference call from prison, speaking with family members. Relatives shown include his brother Joe Peterson and sister-in-law Janey on the upper left, his sister Susan and her husband Ed Caudillo, and Lee Peterson, his father, in the bottom middle.

Caudillo is modeling navy blue coveralls they had just purchased for Lee.

The family tries to schedule a call at least once a week, but due to prison limitations, they are only granted once or twice a month, they said.

After a trial that attracted nationwide attention, California fertilizer salesman Scott Peterson, 32, was found guilty on November 12, 2004 in the Christmas Eve 2002 murder of his pregnant wife Laci. A photo from a program card from a memorial service for Laci Peterson and her unborn son is shown in this May 4, 2003 file photo. REUTERS/Lou Dematteis LD/MR

After a trial that attracted nationwide attention, California fertilizer salesman Scott Peterson, then 32, was found guilty on Nov. 12, 2004 in the Christmas Eve 2002 murder of his pregnant wife Laci. A photo from a program card from a memorial service for Laci Peterson and her unborn son is shown in this May 4, 2003 file photo. (REUTERS)

On April 19, he filed a petition for a writ of habeas corpus in a California appellate court, seeking his release and arguing that the family has uncovered evidence that can prove his innocence.

The 800-page filing has not yet been made public; however, a source tells Fox News Digital it will lay out six claims in connection with his case.

TIMELINE: THE LACI PETERSON CASE

Laci Peterson pregnant posing for photo

Laci Peterson when she was eight months pregnant with Conner when she went missing in December 2002. (AP)

Peterson is expected to renew his claim of juror misconduct, reveal newly unearthed evidence in connection with a burglary right across the street and a possible connection to Laci's disappearance, introduce separate claims that prosecutors presented false evidence on two key issues and suppressed further evidence on one of them, and finally argue that in sum, the other claims merit relief. 

Peterson was transferred in the fall from San Quentin to the Mule Creek State Prison, following his removal from death row.

Scott Peterson speaks with lawyer Cliff Gardner in court

Scott Peterson, right, talks with attorney Cliff Gardner during a hearing at the San Mateo County Superior Court in Redwood City, Calif., Monday, Feb. 28, 2022. In 2004, Peterson was convicted of the murders of his wife, Laci Peterson, 27, who was eight months pregnant, and of the unborn son they planned to name Conner.  (AP Photo/Jeff Chiu, Pool)

At the time, Janey Peterson told Fox News Digital that the family has evidence she believes can prove his innocence.

"We can show that Scott is innocent, and he’s wrongfully convicted of the murder of Laci and Conner," she said.

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While the judge in December declined to order a new trial, some of that evidence is expected to be made public after Peterson's habeas corpus filing.

He had filed two prior petitions in 2012 and 2015, but neither succeeded.

The new filing was expected, according to his sister-in-law, who told Fox News' Laura Ingle earlier this year that she expected to see it by the April 19 deadline.

WATCH: Scott Peterson's request for new trial denied

"He is actually, for the most part now lawyer-less, so he will be filing this petition pro se, representing himself," she said. 

Court records show that's what he did, but she added that he hopes to be assigned counsel to address the new claim.

Peterson lost access to his previous lawyers at the end of the December proceedings, she said.

Read the judge's December decision (Mobile users go here)

SCOTT PETERSON EX-GIRLFRIEND AMBER FREY SPEAKS OUT AFTER NEW TRIAL DECISION: ‘TRUTH DOESN’T CHANGE OVER TIME'

Those involved allegations surrounding misconduct from Richelle Nice, who served as Juror No. 7 in the original trial. In her jury questionnaire, Nice denied having been the victim of a crime or having been involved in a prior lawsuit, according to Peterson’s defense team.

Richelle Nice in cuort in 2004

In this Dec. 13, 2004 photo, Juror number 7, Richelle Nice, adjusts her hair as members of the jury speak with the media in the Old San Mateo County Courthouse in Redwood City, Calif. Nice, a former juror who helped convict Scott Peterson and send him to death row, testified on whether she lied about her history with domestic violence.  (AP Photo/Lou Dematteis, Pool, File)

But Peterson's previous lawyers alleged she hid the fact that she had been beaten, while pregnant, by a boyfriend in 2001 and that on another occasion, pregnant with a different child, she obtained a restraining order against a boyfriend’s ex.

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Scott and Laci Peterson in split image

In this March 17, 2005, file photo, Scott Peterson is escorted by two San Mateo County Sheriff's deputies to a waiting van in Redwood City, Calif. Inset: A portrait of Laci Peterson. (AP Photo/Justin Sullivan)

They argued that Nice’s status as a domestic violence survivor biased her in the case and that she purposely tried to get onto the jury, claims she denied for years before the failed appeal in 2022.

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Judge Anne-Christine Massullo in December ruled that the juror had acted out of emotion, rather than a bias against Peterson, and that she made "honest mistakes." Nice's conduct was not prejudicial, she found.

Fox News' Stephanie Pagones contributed to this report.