Convicted killer Scott Peterson was back in court Wednesday in his latest bid for a new trial.

Peterson attended court in Redwood City via Zoom from Mule Creek State Prison in Amador County where he is currently serving a life sentence after he was convicted in 2004 of killing his wife, Laci Peterson, and her unborn son, Connor.

Peterson’s lawyers with the Los Angeles Innocence Project — who took up the case in January — are requesting evidence from the original investigation undergo new DNA testing.

That includes a bloody mattress found in a burned-out van near Peterson’s home in Modesto shortly after his wife had gone missing.

The mattress had “stains that tested presumptively positive for blood,” but “only a very small portion of the mattress fabric was tested for DNA,” lawyers claimed in court documents. They said that testing was “insufficient to determine whether DNA from Laci and/or Conner was present.”

Detectives discovered there had been a burglary just across the street from where Peterson lived with his pregnant wife. One witness told police she believed that the burglary happened the same morning Laci Peterson disappeared.

Bryan Spitulski, a former fire investigator who responded to the crime, believes the van may be relevant to Laci Peterson’s murder. Spitulski was working for the Modesto Fire Department on Christmas morning in 2002, one day after Laci Peterson disappeared, when he was sent to investigate the van fire.

Sputulski, who currently works as a private fire investigator, previously told CBS News the presumptive positive sample he sent to the Justice Department came back negative for human blood when it was initially tested. 

“So, imagine my shock when I found out just a few years ago that it did test positive for human DNA. I had no clue up to this point,” he said last month. “I literally got goosebumps and the hair on the back of my neck stood up because it does mean something. It is significant.”

Sputulski said his goal isn’t to free or exonerate Peterson, and — unlike the LA Innocence Project — he has not accused authorities of purposely ignoring the possibility of the van being important in the original investigation. 

“I think now that we are aware of it, somebody should allow that to be looked at and to be identified as yes or no, whether it’s an issue or not an issue, human DNA or it’s not. Then we are done with it and it’s over it,” he said.

Peterson was sentenced to death in March 2005. He had admitted to police he was fishing on the day his wife disappeared but during the trial, he could not explain what type of fish he was trying to catch that day. Peterson had also sold his wife’s car, researched selling their house, and turned the baby nursery into a storage room in the weeks after Laci disappeared.

The California Supreme Court in 2020 overturned Peterson’s death sentence after finding that potential jurors were improperly dismissed after saying they disagreed with the death penalty but would follow the law and impose it. 

In 2021, Peterson was resentenced to life in prison without parole under the glaring eyes of Laci Peterson’s family. Peterson was moved from San Quentin State Prison, now known as San Quentin Rehabilitation Center, to Mule Creek State Prison east of Sacramento in 2022.

Later that year, a judge denied Peterson’s plea for a new trial, ruling that a former juror was not guilty of misconduct during the trial.