They say Duane Deaver -- the SBI agent who testified in Peterson's case -- cannot be trusted.
During testimony, the then-confident SBI analyst told the jury about the crime scene in the death of Peterson's wife, Kathleen. Deaver said the spattering of blood was consistent with a beating.
Peterson told ABC11 Wednesday that Deaver lied and he can prove it.
"Yeah, I can tell you that because I didn't kill Kathleen," Peterson said. "I don't know what happened to Kathleen. I believe that she fell. So for this man to come in and say that I hit her however many times ... I think is like 38 times he did it is ridiculous."
Peterson says prosecutors based his case on assumptions investigators made on the scene and that Deaver was determined to frame him no matter what.
"He was the only person who said, I killed Kathleen," Peterson said. "He made this up. Jill Harden -- who is the district attorney -- said over and over again, how crucial, how critical Deaver's opinions were. He was essential for my conviction."
Peterson's case is among 200 others called into question following a scathing review last year that revealed Deaver overstated or falsely reported blood tests in multiple criminal cases. Deaver lost his job with the SBI last month.
Peterson believes in his own case Deaver not only deceived jurors, but also Judge Orlando Hudson, who presided over the trial.
"I'm sure that if judge -- well I would certainly hope -- that if Judge Hudson had known what a fraud this guy was, he never would have let him be an expert," he said.
Peterson has been behind bars since his 2003 conviction.