‘Warrior gene’ appeal to be heard by New Mexico Supreme Court
Is it junk science or a breakthrough that could help identify and treat people with a genetic predisposition to violence?
The so-called warrior gene theory has been hotly debated since a Dutch scientist discovered in the early 1990s that all the male relatives in a New Zealand family with a history of aggressive violence lacked a specific gene critical for regulating anger.
The theory — that people with low levels of a certain enzyme, who are also abused in childhood, are prone to impulsive violence — has been used as a murder defense twice in the United States.
One of those cases was in Santa Fe in 2015, when the public defender for a man accused of first-degree murder attempted to introduce evidence on the topic to cast doubt on his client’s ability to form the intent required to convict him of the charge.
The science was still so new then that the New Yorker sent a writer to Santa Fe to cover a hearing in the case.
District Judge Mary Marlowe Sommer ended up rejecting the argument and did not allow the jury to hear expert testimony on the warrior gene.
But the state Supreme Court recently agreed to review an appellate ruling in the case, which could result in a decision that would set precedent in New Mexico and provide an example to courts around the country on how to apply novel theories about behavioral genetics in the courtroom.
The warrior gene theory has been introduced in criminal proceedings fewer than a dozen times worldwide — twice in Italy and nine times in the United States — since the first study on the topic was published in 1995, according to a 2017 report in the International Journal of Law Psychiatry.
Seven of the nine times warrior gene science was introduced in the U.S., the journal reports, it was raised in the sentencing portion of a criminal case as a mitigating factor to argue for a reduced sentence.
When the Santa Fe Public Defender’s Office attempted to introduce testimony about the genetic theory in the defense of Anthony Blas Yepez, who was charged in the beating, choking and burning death of a 75-year-old Santa Fe man, it was only the second time it had been used in the guilt phase of a trial.
The killing occurred in 2012 during a domestic incident that erupted between Yepez and his girlfriend’s step-grandfather, George Ortiz.
Yepez, then 26, and his girlfriend, Jeannie Ann Sandoval, then 30, had recently come from California and had been staying with Ortiz in his apartment in a senior housing complex on Luisa Street while they looked for work.
The violence that ended in Ortiz’s death began when Ortiz struck Sandoval in the face, according to testimony she gave during Yepez’s trial.
Yepez said he didn’t remember exactly what happened next, only that he “must have blacked out.” When he regained consciousness, he was on top of Ortiz, who was bleeding profusely from the back of his head and appeared to be dead.
The couple then poured cooking oil over Ortiz’s body and set it ablaze before fleeing in Ortiz’s car.
Three months before the case went to trial in state District Court, his defense lawyers told the judge they planned to call expert witnesses to testify about studies that had shown people who have low levels of an enzyme known as monoamine oxidase A, or MAOA — which breaks down neurotransmitters, including serotonin, which is believed to help regulate mood — are more likely to be impulsively aggressive.
That’s particularly true, experts claim, if these individuals were abused as children — as, they said, Yepez had been.
His attorneys said Yepez’s MAOA level was about 1 on a scale of 1 to 5, with 5 considered normal. They said that cast doubt on whether the killing was premeditated and that his MAOA level was his best and only defense against the charge of first-degree murder.
But the judge refused to allow jurors to hear testimony on the still-developing theory — saying she felt “iffy” about whether it was “reliable enough to prove what it proposes to prove.”
A Santa Fe County jury subsequently convicted Yepez of second-degree murder and sentenced him to 22 years in prison.
Yepez appealed his conviction on the grounds the warrior gene evidence should have been allowed.
The state Court of Appeals ruled in July that Sommer erred when she excluded expert testimony, saying it met standards for admission. But the court also determined the mistake was harmless — because Yepez had been convicted of second-degree murder, which does not require the state to prove premeditation — and affirmed the defendant’s sentence, determining no further action was necessary.
Neither the prosecution nor the defense were satisfied with the appellate ruling, but for different reasons. Both submitted petitions asking the state Supreme Court to re-examine the appellate court ruling.
L. Helen Bennett, representing Yepez under contract with the Law Offices of the Public Defender, says Sommer abused her discretion when she decided a proposed witness incorrectly interpreted the studies, because weighing the credibility of expert testimony is the jury’s job.
Bennett cites case law that says “shaky” but admissible evidence should be countered by rebuttal witnesses and aggressive cross-examination — not excluded.
The fact that Yepez was not convicted of first-degree murder does not make the matter moot, Bennett says, because had jurors heard about the genetic and environmental factors that predisposed him to violence, they might have found him guilty of a lesser crime or not guilty.
Bennett is seeking a retrial for Yepez.
“Science changes the way we look at the world, ” Bennett said in a recent interview. “And the courts have an interest and possibly even an obligation to understand those changes and to incorporate new scientific thoughts. Fifty years ago, we didn’t have DNA, and if we were still operating as if DNA didn’t exist, we’d be catching far fewer criminals today.”
Assistant Attorney General Maris Veidemanis claims the Court of Appeals overreached when it published an opinion stating the judge should have allowed the testimony. Veidemanis wrote that judicial protocol requires the court to only decide issues necessary for disposition of the appeal.
After determining the error was harmless and required no redress, Veidemanis argues, the state should have stopped there. She says that if the appellate court’s opinion that warrior gene evidence should have been allowed stands in the Yepez case — a conclusion she argues was reached without a full analysis — it could create confusion in state and federal courts going forward.
The state is asking the state Supreme Court to vacate the portion of the appellate opinion finding Sommer erred in keeping out the warrior gene testimony and leave only the portion of the opinion affirming Yepez’s conviction.
That position also was held by Emil Kiehne, one of the three appellate court judges who reviewed the case.
Ian Loyd, the former Santa Fe public defender who introduced the concept of using the warrior gene defense in the Yepez case, said he’s happy the Supreme Court has agreed to review the case.
“The law has pretty outdated concepts of human behavior,” Loyd said.
“The ‘reasonable man’ standard, I think, is outdated,” he added, referring to a common judicial protocol in which jurors are asked to judge the actions of defendants based on what a “reasonable” person would do.
“I don’t think there is any one reasonable man. Everyone is unique,” Loyd said. “And if there are more ways for the court to better understand why someone behaved in a particular way, at a particular time, maybe you could identify these deficiencies in people and treat them and avoid tragedies like the one in Mr. Yepez’s case.”