In Texas, a New Law Lets Defendants Fight Bad Science
Scientific evidence can be the most convincing element of a criminal trial. But sometimes it's wrong—and for the first time, a state's justice system has recognized that and adjusted accordingly.

Rigoberto “Robert” Avila is supposed to be dead by now.
Avila, a 40-year-old death row inmate in Texas, was supposed to be executed by lethal injection on January 15, 2014. He owes the past six weeks of his life to a groundbreaking new Texas law, the only one of its kind in the nation, which recognizes that science can get it wrong.
The crime that Avila was convicted of, and that he has steadfastly claimed he didn’t commit, is truly difficult to fathom: the murder of a 19-month-old boy. On the night of March 29, 2000, Avila, then 27, was babysitting his girlfriend’s two sons, 19-month-old Nicholas and 4-year-old Dylan. Avila told police that he’d been watching a basketball game in another room when Dylan, visibly scared, told him from the hall that Nicholas wasn’t breathing. Avila ran to the back bedroom where the brothers had been playing alone and found the toddler lying on the floor, next to a child-sized bed. He carried the boy to the living room and called 911. The operator walked him through CPR. It didn’t work. Nicholas died on his living room floor.
Dylan told investigators that he and Nicholas had been roughhousing when Nicholas stopped breathing; Avila was not in the room. Police and doctors, however, had an alternate version of what happened, informed by a large bruise on Nicholas’s torso and by his devastating and irreparable internal injuries, so severe that his organs were ripped from his spine, his pancreas ruptured and his colon torn. They believed that Avila intentionally, maliciously stomped on the toddler’s stomach. Just over a year later, Avila was in court. The trial took only three and a half days; he was convicted of murder and, on July 19, 2001, was sentenced to death.
There were two reasons jury believed that Avila—a Naval veteran with no history of violence or criminal background—was capable of stomping a 19-month-old child to death. The first was that Avila had supposedly confessed to the crime. In his first statement to police, Avila said that he’d been in another room when Dylan told him that Nicholas was hurt. But in a second, much-contested statement, he allegedly admitted that he was jealous of the little boy and that he stomped on him in a rage: “I saw him laying on the floor,” the second statement reads. “I don't know what came over me, but I walked over to him and stamped on him with my right foot.” Avila claims that the detective who took both statements made up the second, and that he only signed it because the detective told him it was a “clarification” of the first. “He didn’t realize until after that it contained this very incorrect story,” said his lawyer, Cathryn Crawford of the Texas Defender Service; Avila testified as much in court. Notably, the second statement was not recorded, while the first was, and it was only signed by Avila, whereas he initialed all of the paragraphs in the first.
The second reason seemed much harder to refute: Medical experts at the time claimed that there was no other possible explanation for the child’s death. The county’s medical examiner testified that the toddler’s injuries could not have been inflicted through roughhousing with his older brother. And during the trial, the pediatric surgeon who’d worked on Nicholas the night he died told the court that there was no way that a 4-year-old could have inflicted the injuries, unless he’d dropped on the boy from a height of 20 feet.
Except that’s not true.
The medical examiner and pediatrician who examined Nicholas didn’t know what forensic pathologists, a physicist, and a biomechanical engineer would later find: A child, even a 40-pound 4-year-old, jumping directly on to the abdomen of a 19-month-old could have most certainly inflicted the kinds of injuries that killed Nicholas. As forensic pathologist John Plunkett explained in an April 2013 affidavit, few scientists at the time were capable of understanding the biomechanics involved in Nicholas’s death, in part because little research had been done on these kinds of injuries. Plunkett said it was imperative that a qualified biomechanical engineer or physicist perform the necessary experiments to investigate Nicholas’s injuries.
So Avila’s legal team found someone to do just that. In May 2013, biomechanical engineer Chris Van Ee conducted an experiment envisioning what could have happened if Dylan had jumped on Nicholas from a height of 18 inches – the same height as the small bed next to which Nicholas was found lying unresponsive. Van Ee, summing up his conclusion in a report that accompanied Avila’s writ, found that a child of Dylan’s size jumping from that height could produce a force as great as 400 to 500 pounds.
In the past, Van Ee’s findings might not have been enough to delay Avila’s execution, or potentially reverse his verdict. But that same month, Texas passed a bill called SB 344, better known as the “junk science” statute. The first of its kind in the nation, it permits a defendant to bring a writ of habeas corpus on the basis of new or changed scientific evidence. In practical terms, this means that courts must grant relief in cases where new scientific evidence has come to light, or where scientific evidence used to convict has been shown to be false, misleading, or inaccurately applied. The statute keeps the court from denying relief even if the defendant had previously confessed or accepted a plea. It also, crucially for Avila, does not require anyone to recant his or her original testimony.
The statute has allowed Avila to request a new trial based on the claim that inaccurate medical testimony put him on death row “If the medical examiner hadn’t testified that the only way this injury could have been inflicted was by an adult, I don’t think they would have convicted,” said Crawford, Avila’s lawyer. “Bad science is what lead to his conviction in the first place and that’s really what the law is—a recognition that doctors can be wrong, not through laziness or through any incompetence but because of the state of the science at the time that they render these decisions.”
The state agreed enough to postpone Avila’s execution; now, the Court of Criminal Appeals is considering his request for a new trial. For Avila, the statute offered him a last chance – he was running out of reasons to appeal, and this was the fourth time his execution had been postponed.
The same statute has already been invoked two other high-profile Texas appeals cases, those of Frances and Dan Keller and the San Antonio Four. In each case, the defendants were convicted of sexual assault of a child and insisted that “junk science” had played a large part in their convictions. In 1991, the Kellers were running a daycare in Oak Hill, Texas, when a 3-year-old girl in their care accused the couple of sexual abuse; this was during a period in the 1980s and ’90s when people believed that Satanic cults were infiltrating the very fabric of society, a paranoia that clearly colored the investigation and trial. The one piece of physical evidence against the couple was that an emergency room doctor who’d examined the girl said that “lacerations” to her labia were consistent with sexual abuse. As it turns out, the “lacerations” in question were really just natural variations of vaginal appearance and the doctor recanted his testimony. (In 2007, the American Academy of Pediatrics published a long-ranging study confirming that sexual abuse doesn’t generally leave hymenal scarring. While some of this research would have been available at the time of the Kellers’ conviction, it wasn’t widely known.) The Kellers were released from prison this past fall and are awaiting their chance to prove their innocence.
Similarly, the San Antonio Four—Elizabeth Ramirez, Cassandra Rivera, Kristie Mayhugh, and Anna Vasquez—were convicted in 1994 of raping Ramirez’s then 9 and 7-year-old nieces. According to the doctor who examined the older girl, she bore “scarring” on her hymen, which was later found to be normal vaginal variation; this doctor also recanted her testimony. The women, three of whom were still in prison and one who was already out on parole, were all released in November and are now pursuing their innocence claim with the State of Texas.
For Texas—the state that leads the nation in executions—the new law may be a major step toward more careful and precise verdicts. “It is a recognition by the legislature that science is constantly evolving and our legal system has to evolve with it,” said Crawford.
And for the rest of the country, it’s an opportunity to watch and learn. Mike Snedeker, president of the non-profit National Center for Reason and Justice, described the new law as “elegant and straightforward, and “phenomenally important,” not the least because it clarifies and builds on existing due process rights. In theory, defendants should always be able to bring a writ of habeas corpus on the grounds of new information; in practice, however, outside of cases involving DNA evidence, it’s difficult to do this.
“You could say that the principles it embodies are already part of the federal constitution, but that’s sort of a fuzzy document and the judges that enforce it are distant… They don’t have nearly the credibility that a law passed by your own state has,” said Snedeker. “[The law] makes it clearer, it makes it definite, not an arguable constitutional principle, but rather it’s a state statute that clearly describes when and how you can challenge a conviction based on evidence we now know to be wrong.”
The new statute offers another kind of clarity: “It’s important because a lot of really shaky evidence is clothed in objectivity,” said Snedeker, noting the incalculable impact expert testimony can have on a juror’s decision-making—especially expert testimony characterized as scientific or medical. “Our priests now are scientists, doctors,” said Snedeker. By giving defendants a way to question the sacrosanctity of scientific testimony, the court recognizes that science and medicine are mutable and continually evolving. (It’s notable that all three cases—Avila, the Kellers, and the San Antonio Four—involved children. Crimes involving minors can be particularly fraught and difficult for jurors to navigate, which often makes them more inclined to rely on “hard” evidence. As Snedeker put it, “Children are at the center of our need to have someone to blame. The idea that the random nature of things would take our child is so much harder to deal with.”)
There is, however, one important thing the new statute can’t do: keep bad science out of the courtroom in the first place. Expert witnesses can still draw dubious conclusions about blood spatter patterns, employ much-contested approaches like dog scent line-ups, or try to divine an alleged arsonist’s intentions based on “crazed glass” patterns in windows. This makes Keith Hampton, a lawyer for the Kellers who used the statute in their habeas corpus writ, only cautiously optimistic about the new law. . “A junk science bill that I would get most excited about is the one that prevents junk from coming into the court room in the first place,” he said. “And this absolutely does not, that’s plain. It’s put in the post-conviction chapter in the code of criminal procedure.”
But Snedeker is nevertheless hopeful that the law will influence how cases look in the future. “I think it will definitely make prosecutors think twice,” he said.
And ultimately, he’s impressed: “I’m just stunned, [because] I never thought there would be a time in my life when Texas would be a beacon of legal progress.”