Establishing Sufficiency Standards for Expert Medical Testimony and Circumstantial Evidence in Intentional Child Abuse Resulting in Death: State v. Soto

Introduction

State v. Soto, decided by the Supreme Court of New Mexico on March 27, 2025, is a capital-appeal case in which the court reaffirmed and clarified the standards governing the sufficiency of expert medical testimony and complementary circumstantial evidence in prosecutions for intentional child abuse resulting in death (NMSA 1978, § 30-6-1(D),(H)). The defendant, Ricardo Soto, was convicted in the District Court of Lincoln County for severely abusing his two-year-old son, Jeremiah Nevarez, leading to the child’s death. Soto raised three principal challenges on appeal:

The sufficiency of expert medical testimony to prove beyond a reasonable doubt that he intentionally inflicted the fatal injuries;
The district court’s pretrial ruling permitting introduction of his prior perjury conviction in rebuttal if he presented character-of-parent evidence;
The admission of statistical evidence comparing fatal outcomes from falls versus abusive trauma.

In a unanimous opinion authored by Justice Zamora, the court rejected all three arguments, affirmed the conviction, and issued guiding principles for trial courts on handling expert testimony and circumstantial evidence in child abuse death cases.

Summary of the Judgment

The Supreme Court of New Mexico held:

Sufficiency of Evidence: The aggregate of expert medical testimony (identifying two skull fractures, catastrophic brain swelling, and “high-energy” blunt force trauma shortly before death), corroborated by non-medical evidence (sole adult custody, irregular visitation, delayed 911 call, and suspicious flight to Mexico), satisfied the “beyond a reasonable doubt” standard. Consaul, the court’s prior sufficiency-of-evidence decision, was distinguished because Soto’s experts provided conclusive cause-and-effect testimony rather than mere suspicion.
Prior Conviction Rebuttal: Although the district court’s pretrial order may have mis-cited Rule 11-404(A)(2) regarding character-of-parent evidence, any error was harmless. In any event, evidence of Soto’s perjury conviction was admissible under Rule 11-404(B)(2) and UJI 14-5003 to show consciousness of guilt.
Statistical Evidence: The trial court did not abuse its discretion in admitting expert statistical testimony (e.g., “one in two million” odds of serious injury from a short fall; 600-to-1 ratio of death by abuse versus short fall). These numbers were properly founded, highly probative on mechanism of injury, and not misleading.

The appellate court affirmed Soto’s conviction and life sentence, and provided detailed guidance on expert testimony and evidentiary rulings in child‐abuse death prosecutions.

Analysis

Precedents Cited

State v. Consaul (2014‐NMSC‐030): Held insufficient medical testimony when experts expressed only suspicion, inability to rule out other causes, or lack of specific force analysis. Distinguished in Soto because the experts here offered definitive, mechanism-based opinions and a clear timeline.
State v. Sena (2008‐NMSC‐053): Reaffirmed that sufficiency review requires viewing all evidence in the light most favorable to the verdict and ensuring substantial evidence for each element.
State v. Baca (1997‐NMSC‐059) and State v. Cunningham (2000‐NMSC‐009): Defined “substantial evidence” and reviewed the standard of viewing evidence in the prosecution’s favor.
State v. Wilson (2001‐NMCA‐032) and related cases: Supported admission of opportunity evidence—defendant was sole adult present during injury window.
State v. Martinez (2008‐NMSC‐060): Clarified character evidence rules under Rule 11-404, including permissible rebuttal.
Rule 11-404 NMRA and UJI 14-5003: Governing character evidence and statements showing consciousness of guilt.

These precedents set the stage for Soto’s precise refinements on the admissibility and sufficiency of expert and circumstantial evidence in child abuse fatalities.

Legal Reasoning

Justice Zamora structured the opinion around three major questions:

Was the medical and circumstantial evidence sufficient?
- Experts identified two distinct skull fractures (parietal and occipital), massive intracranial hemorrhage, midline shift, and brain stem compression—unmistakable signs of high-energy blunt impact within a narrow time frame.
- Medical certainty: Witnesses testified “to a reasonable degree of medical certainty” that these injuries could only result from violent trauma, not a short fall or chronic bleed.
- Circumstantial corroboration: Defendant’s sole custody during injury window; inconsistencies in his behavior (delayed 911 call, flight to Mexico); sporadic paternal relationship.
- Distinguishing Consaul: Soto’s experts went beyond “suspected abuse” to specify force, mechanism, and timing, and the State presented robust non-medical evidence supporting intent.
Was the court’s pretrial ruling on Soto’s perjury conviction correct?
- Rule 11-404(A)(2) permits defendants to introduce character evidence of good parenting; rebuttal must be confined to that trait. A perjury conviction is not character evidence of parenting, so it would have been inadmissible under that rule.
- However, Rule 11-404(B)(2)/UJI 14-5003 allow admission of other-act evidence showing “false or deliberately misleading statements” as proof of consciousness of guilt. Soto’s pretrial order cited these provisions as well.
- The court’s mid-trial refusal to revisit its ruling based on “law-of-the-case” was a discretionary, fairness-based decision and was not an abuse of discretion.
- Even if erroneous under Rule 11-404(A)(2), the error was harmless in light of the overwhelming expert and circumstantial evidence.
Was statistical expert testimony unduly prejudicial?
- Rule 11-702 requires foundation for expert methodology. Soto lodged no foundational challenge; both experts were qualified pediatric specialists relying on recognized data sources (CDC statistics, peer-reviewed studies).
- Rule 11-403 balancing: The statistics (e.g., one in two million chance of severe injury from a short fall; 600:1 ratio for fatal abuse vs. fall) were highly probative on injury mechanism and did not mislead or confuse the jury.
- Julian (Cal. App. 2019) rejected statistical evidence used to bolster witness credibility in sexual-abuse trials. Here, statistics were not used to prove a witness’s truthfulness but to explain biomechanical probability.

Impact

State v. Soto provides important guidance for future child abuse death prosecutions:

Expert Testimony: Trial courts should permit medical experts to explain their differential-diagnosis process, specify force mechanics, and state their conclusions “to a reasonable degree of medical certainty,” without artificially limiting them to “consistent with” language that undermines clarity.
Sufficiency Review: Appellate courts will uphold convictions when medical experts conclusively tie injuries to non-accidental trauma and when corroborating circumstantial evidence establishes opportunity, intent, and consciousness of guilt.
Character-Evidence Rulings: Distinguishes between character evidence offered by a defendant (Rule 11-404(A)(2)) and “other-act” evidence used to show consciousness of guilt (Rule 11-404(B)(2) and UJI 14-5003). Trial courts should carefully frame pretrial orders to avoid confusion.
Statistical Data: Validates use of well-founded statistical probabilities—when properly explained—to assist jurors in understanding rare injury patterns.

Complex Concepts Simplified

Differential Diagnosis: A structured process by which a medical expert rules in or out various causes of injury or disease to arrive at the most likely explanation, based on examination, imaging, and scientific literature.
Subdural Hematoma: Bleeding between the brain surface and its protective covering (the dura), which can increase intracranial pressure and shift brain structures, potentially causing death.
Consciousness of Guilt: Actions by a defendant after an alleged crime—such as fleeing, making false statements, or tampering—used to infer that the defendant knew of his own wrongdoing.
Rule 11-404 NMRA: Governs when character evidence is admissible. Subsection (A) limits propensity evidence; subsection (B) permits “other-act” evidence for non-propensity purposes (motive, intent, consciousness of guilt, etc.).
Plain Error vs. Abuse of Discretion: Plain Error: A clear, fundamental mistake that affects substantial rights and fairness when no timely objection was made.
Abuse of Discretion: A ruling so unreasonable or arbitrary that no reasonable judge would make it.

Conclusion

State v. Soto stands as a leading decision on the sufficiency of medical expert testimony and supporting circumstantial evidence in intentional child abuse resulting in death cases. It clarifies that:

Medical experts must be allowed to explain their reasoning, rule out alternative causes, and state firm conclusions about cause and timing of injuries.
Circumstantial evidence—defendant’s opportunity to commit the abuse, delayed emergency response, and flight—reinforces medical findings and supplies proof of intent and consciousness of guilt.
Statistical probabilities, when properly founded and explained, can help juries assess how likely a given injury mechanism is among alternative scenarios.
Trial courts must clearly distinguish between character evidence offered by a defendant and “other-act” evidence used to demonstrate consciousness of guilt, to avoid unfair surprise and unnecessary appeals.

This judgment will guide trial judges, defenders, and prosecutors in structuring evidence presentations and ensure that juries receive both the clarity and completeness they need to decide complex abuse cases fairly and accurately.