State v. Yepez

• Decision Date: 25 February 2021
• Docket Number: No. S-1-SC-37216 CONSOLIDATED WITH No. S-1-SC-37217,S-1-SC-37216 CONSOLIDATED WITH No. S-1-SC-37217
• Citation: 483 P.3d 576
• Parties: STATE of New Mexico, Plaintiff-Petitioner/Cross-Respondent, v. Anthony Blas YEPEZ, Defendant-Respondent/Cross-Petitioner.
• Court: New Mexico Supreme Court

483 P.3d 576

STATE of New Mexico, Plaintiff-Petitioner/Cross-Respondent,

v.Anthony Blas YEPEZ, Defendant-Respondent/Cross-Petitioner.

No. S-1-SC-37216 CONSOLIDATED WITH No. S-1-SC-37217

Supreme Court of New Mexico.

Filing Date: February 25, 2021

Hector H. Balderas, Attorney General, Maris Veidemanis, Assistant Attorney General, Santa Fe, NM, for Petitioner/Cross-Respondent.

L. Helen Bennett, P.C., Linda Helen Bennett, Albuquerque, NM, for Respondent/Cross-Petitioner.

NAKAMURA, Justice.

{1} Defendant Anthony Blas Yepez (Yepez) was convicted of, among other crimes, second-degree murder. At issue before this Court is the district court's exclusion of proposed expert testimony concerning Yepez's alleged genetic predisposition to impulsive violence—testimony Yepez offered on the issue of whether he had the deliberate intent to kill. We hold that the district court did not abuse its discretion by excluding the testimony. Accordingly, we reverse the Court of Appeals’ holding on this issue, reject Yepez's cross-appeal, and affirm his conviction.

I. BACKGROUND

{2} The relevant facts are undisputed and correctly summarized in the Court of Appeals’ opinion, so we need not repeat them in detail here. State v. Yepez , 2018-NMCA-062, ¶¶ 2-6, 428 P.3d 301. Yepez and his girlfriend, Jeannie Sandoval (Sandoval), lived with George Ortiz (Ortiz), the boyfriend of Sandoval's adoptive mother. On October 29, 2012, Yepez killed Ortiz during an argument, after which Yepez and Sandoval set fire to Ortiz's body. Id. ¶¶ 3 -4. Ortiz's autopsy concluded that his cause of death was homicidal violence and thermal injuries, and that the manner of death was homicide. Id. ¶ 6. The State charged Yepez with (1) first-degree murder, (2) conspiracy to commit first-degree murder, (3) tampering with evidence, and (4) unlawful taking of a motor vehicle.

A. The Defense's Proffered Expert Testimony

1. Pretrial motions

{3} Before trial, Yepez filed a motion in limine to admit expert testimony to the effect that Yepez "experienced maltreatment in childhood" and has a genotype¹ that confers low levels of monoamine oxidase A (MAOA)² activity, which in combination produce "maladaptive[ ] or violent[ ] behavior." He emphasized that "[t]his testimony will serve as almost the entire basis of [his] defense" to first-degree murder. One month later, Yepez filed a so-called "Notice of Incapacity to Form Specific Intent," stating his plan to call an expert "on the issue of whether [Yepez] was incapable of forming the specific intent required as an element of the crime charged," namely, first-degree murder, and referring to the proposed expert testimony on Yepez's genetic predisposition to violence. Yepez also filed an amended motion in limine clarifying that he was requesting a hearing on the admissibility of this genetic evidence. Yepez identified a number of potential experts in the foregoing motions, including a neuropsychologist, James S. Walker, Ph.D., and a geneticist, David A. Lightfoot, Ph.D., whose report on Yepez's MAOA genotype was appended to the original motion in limine.

{4} The State then filed its own motion in limine seeking to exclude the defense's proposed expert testimony. The State did not dispute the qualifications of the proffered experts but argued that the proposed evidence was not relevant or reliable under Rule 11-702 NMRA, Daubert v. Merrell Dow Pharmaceuticals, Inc. , 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993), and State v. Alberico , 1993-NMSC-047, 116 N.M. 156, 861 P.2d 192. Specifically, the State contended that the alleged predisposition to violence resulting from a low-activity MAOA genotype and childhood maltreatment is not yet understood with sufficient precision to be reliable or relevant as a predictor of violence in individuals. The State further argued that Yepez's self-reported childhood maltreatment was uncorroborated and self-serving. Finally, the State contended that the proposed expert testimony would mislead and confuse the jury due to the complexity of the testimony and the jury's susceptibility to a deterministic interpretation.

2. Daubert/Alberico hearing

{5} At the Daubert / Alberico hearing, Yepez presented the testimony of Walker, Rose McDermott, Ph.D., a political scientist and psychologist with expertise in the behavioral sciences, and Adrian Raine, Ph.D., a psychologist. All three witnesses based their opinions on research purportedly supporting a relationship between childhood maltreatment combined with low MAOA activity and predisposition to antisocial aggressive behavior. Among the earliest research is a 1993 study from the Netherlands, focusing on a family in which a genetic mutation resulted in a complete deficiency of MAOA in certain males. H.G. Brunner et al., Abnormal Behavior Associated with a Point Mutation in the Structural Gene for [MAOA] , 262 Science 578, 578-80 (1993) (hereinafter the "Brunner study").³ The study found a relationship between "isolated complete deficiency of MAOA activity and abnormal aggressive behavior in affected males." Id. at 579-80. This complete deficiency of MAOA, characterized by impulsive aggressive behavior, is known as "Brunner syndrome."

{6} This study was followed by the "classic" Caspi study in 2002, finding that maltreated male children with a genotype conferring low levels of MAOA expression were predisposed to develop antisocial behavior. See Caspi study, supra , at 851, 853. Raine and Walker both testified that the Caspi findings have now been replicated in numerous studies, citing a then-recent meta-analysis of twenty-seven peer-reviewed studies by Amy L. Byrd and Stephen B. Manuck, MAOA, Childhood Maltreatment, and Anti-Social Behavior: Meta-analysis of a Gene-Environment Interaction , 75 Biological Psychiatry 9, 9-17 (2014) (hereinafter the "Byrd and Manuck study").⁴ The meta-analysis included a number of studies which had failed to replicate Caspi's findings, but concluded that the twenty-seven showed, "[a]cross male cohorts," a "moderately reliable interaction of MAOA variation and environmental risk factors, with childhood adversity presaging antisocial outcomes more strongly in persons of low-activity, compared with high-activity, MAOA genotype." Id. at 14. McDermott also testified regarding her recent experiment and report thereon, finding that participants maltreated as children who had low-activity MAOA were more likely to want to punish a perceived aggressor relative to participants with high-activity MAOA.

{7} Walker conducted a forensic neuropsychological examination of Yepez and requested genetic testing of Yepez as an aspect of that examination. In the Daubert / Alberico hearing, Walker explained that he asked Lightfoot to look at Yepez's MAOA gene expression and "tell [him] whether or not Mr. Yepez had a low or high activity of that gene." Lightfoot's report concluded that

the deletion of the MAOA allele in [Yepez] encompasses one or both of the amplification sites. The size of the deletion cannot be determined without further experimentation. However, there can be no doubt that [Yepez] carries a rare mutation in the MAOA gene on [his] single X chromosome. ... Outcomes to be predicted from an MAOA deletion would include aggressive behavior as characterized for Brunner's syndrome ....

{8} Walker opined, based on this report, that Yepez has "an extremely low function of the [MAOA] gene," though he conceded that "[w]e don't know if Mr. Yepez really has the Brunner syndrome, if he really has a no[-]activity gene." Walker also testified that Yepez credibly reported experiencing a "pretty horrific childhood" characterized by significant abuse. When asked his opinion as to the implications of these findings, Walker responded that Yepez "committed an act of impulsive, senseless violence in this particular case," and that Yepez's "history of childhood abuse and ... this low MAOA activity gene made him exceptionally predisposed to committing violent behavior."

{9} After receiving evidence at the Daubert / Alberico hearing, the district court identified the question it was being asked to decide as follows: "whether to allow [Walker] to testify before the jury that—that [Yepez]—the fact that he has a history of child abuse, a low MAOA activity gene made him exceptionally predisposed to committing violent behavior." The district court concluded—with respect to the underlying science drawing connections between childhood maltreatment of males having low levels of MAOA and increased violent behavior—that "in this case, the Daubert factors were met." The court went on, however, emphasizing that, under Rule 11-702 and Alberico , an expert opinion is not of assistance to the jury unless the scientific technique or method upon which it is premised is reliable. Applying this standard, the court stated, "I'm really kind of iffy on whether—whether we've satisfied—whether it's a scientific technique that's reliable enough to prove what it [purports] to prove," observing that the thirty-year longitudinal study referenced in periodicals that the defense provided to the court was "inconclusive" and that there is still "work to be done."

{10} The district court then came to its overall conclusion and said, "here's where I find that the testimony is not going to be admitted." The court explained that no expert had interpreted, or demonstrated his or her qualifications to interpret, Lightfoot's report on Yepez's MAOA genotype. The court noted the statement in Lightfoot's report that "the size of the deletion cannot be determined without further experimentation" and found this to be significant, explaining that

I don't know how low—I didn't hear any testimony educating me on—that this was a low MAOA, and I think what was missing was that you failed to call Dr. Lightfoot. ... I can't find that Dr. Walker's testimony is going to be helpful to the trier of fact because I ... don't have any evidence before me from the person that did the testing that the result was a low MAOA.

3. ...