Twenty-four years after his testimony helped send Jeffrey Prible to death row, DNA expert William Watson has told a Texas court he would testify differently today. In a declaration signed July 31, 2025, Watson says changes in forensic biology, scientific methods, and his own knowledge mean he can no longer support key timing inferences from his 2002 testimony. He also describes parts of the prosecution’s use of his opinions as “scientifically baseless” and “highly inappropriate.”
The lead prosecutor was Kelly Siegler, working with co-counsel Vic Wisner. Oxygen’s profile of Siegler says she spent more than 21 years at the Harris County District Attorney’s Office before resigning in May 2008. She later became the host of Cold Justice and Prosecuting Evil With Kelly Siegler.
The recantation forms part of an August 28, 2026 habeas application asking the Texas Court of Criminal Appeals to allow new claims challenging Prible’s conviction.
The underlying crime is not in dispute. On April 24, 1999, Steve Herrera and Nilda Tirado were found shot to death inside their Houston home. Their three young daughters died from smoke and carbon monoxide inhalation after a fire was set in the house. Prible, a friend of Herrera’s, was convicted of capital murder on October 25, 2002 and sentenced to death.
What is in dispute is how the state got there.
A central piece of forensic evidence came from an oral swab taken from Tirado. It revealed sperm cells whose DNA matched Prible. At trial, Watson testified that his ability to generate a full male DNA profile was consistent with substantial sperm being present and with the semen having been deposited shortly before Tirado’s death. Prible’s account was that his sexual contact with Tirado had been consensual and occurred hours earlier.
Watson’s 2025 declaration no longer supports that timing inference. He says he cannot scientifically determine when the spermatozoa in the oral sample were deposited relative to Tirado’s death, cannot conclude that the oral sample was stronger, purer, or more recent than samples from other locations, and cannot determine the sequence in which the samples were deposited. His declaration says deposition around the time of death remains possible, but it is not the only scientifically supportable explanation.
A second review by forensic DNA specialist Huma Nasir, retained by Prible’s lawyers and included with the new filing, reaches a similar conclusion. Her review says obtaining a full DNA profile from the oral swab does not establish that ejaculation occurred immediately before death and cannot be used to calculate its proximity to the killing.
Watson also repudiates Siegler’s characterization of his expected testimony in her opening statement and key conclusions the state drew from his testimony in closing arguments. The new court filing records him describing those statements as scientifically baseless.
The distance between what a forensic witness said on the stand and what prosecutors told a jury the testimony meant is where much of the dispute in the Prible case now sits.
Prible’s lawyers argue that the state converted qualified scientific testimony into a far more certain narrative: the DNA was treated not simply as evidence that sexual contact had occurred, but as proof that it happened immediately before Tirado was killed and therefore supported the prosecution’s account of the murders.
The case has a second evidentiary layer. In 2020, U.S. District Judge Keith Ellison conditionally granted Prible federal habeas relief on five Brady claims and one Massiah claim. Ellison found that the prosecution had withheld material evidence, including information concerning Siegler’s contacts with jailhouse informants. He described Siegler as intentionally withholding information from the defense, being deceptive about those efforts, and lacking credibility in her federal testimony.
That ruling did not ultimately free Prible. In 2022, the Fifth Circuit vacated the habeas judgment, concluding that Prible had not overcome the procedural default of his claims. The appeals court expressly said it was not reaching the merits of those claims.
Two separate concerns therefore sit on top of the same conviction: a DNA expert who now withdraws key timing conclusions, and a federal district-court record finding that material evidence concerning informants was suppressed. Neither has so far produced final relief for Prible.
The new state filing stitches those strands together. It asks the Texas Court of Criminal Appeals to consider the changed DNA evidence alongside the evidence developed during the federal habeas proceedings.
Around the case, a second story has been running in parallel. Siegler’s career after the DA’s office moved into television. Cold Justice follows Siegler and investigators working with local law-enforcement agencies on unsolved cases. Her second series remains active, but it is not currently airing a new season: Oxygen says season three of Prosecuting Evil premieres October 3, 2026.
The true-crime market has increasingly built shows around former prosecutors, detectives, and investigators. The genre rewards decisive storytelling. Court records, by contrast, are full of qualifications, burdens of proof, procedural bars, and disputes over what evidence can actually establish.
That is not evidence of anything about a specific prosecution. It is context for the unusual split-screen surrounding this case: Siegler’s courtroom career became the basis for a successful television persona while litigation over some of her prosecutions continued in court.
Watson’s reassessment did not begin with the 2025 declaration. A Texas Observer republication of The Intercept’s 2023 investigation records Watson saying that he would testify differently if called again and that some of his trial answers had sounded more “definitive” than they should have. The declaration formalizes that reassessment in a document Prible’s lawyers can put before a court.
What the declaration does not do, by itself, is prove Prible innocent. Prible maintains his innocence, and his new filing argues that the combination of the DNA re-evaluation and evidence concerning the informants undermines the conviction. But an expert’s later reassessment and a judicial finding of constitutional violations are still separate from a final order vacating a conviction.
The Fifth Circuit’s 2022 ruling illustrates another part of the problem. New or disputed evidence can exist while procedural rules still determine whether a federal court reaches the underlying merits at all.
That leaves the case in a familiar tension: an evidentiary record that has changed substantially since trial, and a legal process in which the routes for acting on that change have become narrower with time.
There is an unavoidable mismatch between the way science evolves and the way final criminal judgments operate. Watson’s position today is not simply that he wishes he had phrased an answer differently. His declaration says later scientific developments and his own increased knowledge have changed what conclusions he believes the evidence can support.
DMNews has covered the rise of the prosecutor-as-personality before, and the way true-crime storytelling rewards certainty more readily than evidentiary qualification. The Prible case is not a metaphor for that pattern. It is one specific case, with named participants and a long judicial record, in which the certainty presented to a jury is now being challenged by the expert whose evidence helped create it.
The August 28 application has been filed. Siegler’s television career continues, with Prosecuting Evil scheduled to return in October. The Texas Department of Criminal Justice still lists Prible as a death-row inmate.
Twenty-four years is a long time for the meaning of forensic testimony to change. Whether that change is enough to alter the judgment entered in 2002 is now a question for the Texas courts.