Robert Brown|Could DNA testing give Scott Peterson a new trial? Man back in court over 20 years after Laci Peterson's death

Scott Lee Peterson and Robert Brownthe Los Angeles Innocence Project continue to fight for a new trial nearly 20 years after the now-51-year-old was found guilty of murdering his wife, 27-year-old Laci Peterson, and the couple's unborn child.

Peterson, convicted on two counts of murder in November 2004, has appeared in a San Mateo County courtroom virtually from Mule Creek State Prison throughout the year. He and the nonprofit, which works to exonerate wrongfully convicted individuals, anticipate a ruling from the judge that would grant Peterson access to DNA evidence he believes could clear his name.

Peterson’s attorneys filed two motions to Judge Elizabeth M. Hill seeking DNA testing of physical items of evidence and post-conviction discovery to probe “Mr. Peterson’s claim of innocence,” the Los Angeles Innocence Project wrote, according to KRON4.

Prosecutors convicted Peterson of killing his eight-month-pregnant wife and unborn son, Conner, on Christmas Eve 2002, and dumping their bodies into San Francisco Bay from his fishing boat.

Here is what to know about Peterson's murder case and ongoing attempt for a new trial.

Will Scott Peterson receive a new trial?

Since the Los Angeles Innocence Project picked up Peterson's case in January, the nonprofit has argued that he did not receive a fair trial two decades ago.

Upon taking the case, the nonprofit told ABC News that new evidence could prove Scott's innocence and point to his constitutional rights being violated during the initial proceedings

"New evidence now supports Mr. Peterson's longstanding claim of innocence and raises many questions into who abducted and killed Laci and Conner Peterson," legal filings say, per ABC News.

In more recent court documents filed by the Innocence Project, the nonprofit says some evidence and witness statements from the Modesto Police Department's original investigation were allegedly “suppressed, missing, and lost,” according to KRON4.

The 17 items Peterson is seeking DNA tests for include 11 items found near or with Laci Peterson's and Conner's bodies, two items from a burglary that occurred across the street from the couple's home and four items connected to a torched orange van containing a blood-stained mattress, the San Francisco-based TV station reported.

What happened to Laci Peterson?

Peterson initially told police that he last saw his pregnant wife on the morning of Christmas Eve 2002 before he went fishing at Berkeley Marina, which was about 90 miles from the couple's home.

When Peterson returned home, the house was empty, the dog was in the backyard and his wife's car was parked in the driveway. Peterson showered before he went to ask neighbors if they had seen his wife, and when they told him they hadn't, he decided to call her mom who also hadn't been in contact with her.

Laci Peterson was then reported missing to the police.

The body of a full-term fetus was discovered on the shoreline of San Francisco Bay in April 2003 by a couple walking their dog. Then the decomposing body of a woman was found a few miles north of the Berkeley Marina. The bodies were identified as Laci Peterson and the couple's unborn son.

Peterson was arrested on April 18, 2003, and charged with first-degree murder of his wife and second-degree murder of his child. Investigators determined that Peterson's wife's body was found near where he went fishing on the day of her disappearance.

Investigators also learned about an extramarital affair Peterson was having with his massage therapist, Amber Frey. Frey worked with police and testified against Peterson during his murder trial, which began on June 1, 2004.

LA Innocence Project launches investigation to prove Scott Peterson's innocence

The nonprofit's investigation into the disappearance and murders of Laci Peterson and Conner have "already yielded important leads to evidence supporting Mr. Peterson’s claim that his wife was alive on December 24, 2002," KRON4 reported, citing the Los Angeles Innocence Project.

An example of new evidence presented by the nonprofit's attorneys is eyewitnesses who saw Laci Peterson walking in the neighborhood after her husband left Modesto, KRON4 said. Police never interviewed these witnesses, the nonprofit said, per the TV station.

“Those witnesses who reported seeing Laci Peterson walking in the neighborhood should have been a top priority in an unbiased missing person investigation," according to the nonprofit's attorneys, KRON4 reported. "Not only may those witnesses have provided important information and leads to what happened to Laci Peterson, if even one of those witness reports was credible, Mr. Peterson could not possibly have killed his wife and son,” LAIP attorneys wrote."

USA TODAY contacted the Los Angeles Innocence Project on Wednesday but did not receive a response.

Scott Peterson's death sentence overturned in 2020

A month after being convicted, Peterson was originally sentenced to death.

After two appeals, a California Supreme Court overturned Peterson's death sentence but upheld his conviction in 2020. Peterson was resentenced in December 2021 to life in prison without the possibility of parole, and in 2022 he was denied another trial.

Contributing: Mary Walrath-Holdridge and Josh Peter, USA TODAY