Clarifying Palpable Error Review for Expert Testimony on Victim-Perpetrator Intimacy and Prosecutorial Rebuttal in Kentucky Murder Appeals

Introduction

The Supreme Court of Kentucky’s unpublished opinion in Cocina Penn v. Commonwealth of Kentucky (2025) addresses how unpreserved evidentiary and argument-related errors are evaluated under the “palpable error” standard (RCr 10.26) in a murder prosecution. Appellant Cocina Penn appealed her life sentence for murdering her husband, Robert Penn, claiming (1) improper expert opinion testimony about facial wounds and intimacy, (2) prosecutorial misconduct in closing argument, and (3) cumulative error. The Court affirms, clarifying the scope of expert testimony under Kentucky Rule of Evidence 702 and the prosecutor’s latitude in closing, while reinforcing the high threshold for overturning unpreserved errors.

Summary of the Judgment

On April 24, 2025, the Kentucky Supreme Court affirmed the McCracken Circuit Court’s conviction and life sentence for Cocina Penn. Penn’s three claims—all unpreserved at trial—were reviewed under the palpable error standard. First, the Court held that expert testimony by Dr. Christopher Kiefer, linking facial stab wounds to a close personal relationship, was admissible specialized knowledge under KRE 702 and did not create a substantial possibility of a different outcome. Second, it found no prosecutorial misconduct in comments about “trash pickup day” when rebutting the robbery theory. Finally, with no individual errors, there could be no cumulative error. Penn’s conviction stands.

Analysis

1. Precedents Cited

• Ordway v. Commonwealth (391 S.W.3d 762): Critically examined improper opinion testimony comparing a defendant’s behavior to classes of suspects.
• Rieder v. Commonwealth (474 S.W.3d 143): Distinguished harmless error review from the more exacting palpable error standard under RCr 10.26.
• Brewer v. Commonwealth (206 S.W.3d 343) and Graves v. Commonwealth (17 S.W.3d 858): Established definitions and thresholds for palpable error.
• KRE 702: Permits expert testimony when it will assist the trier of fact by drawing on scientific, technical, or other specialized knowledge.
• RCr 10.26: Allows appellate consideration of unpreserved errors only if they are “palpable”—serious enough to affect substantial rights and render proceedings unfair.

2. Legal Reasoning

2.1 Expert Opinion Testimony and Palpable Error

Penn argued it was error for Dr. Kiefer to testify that facial stab wounds typically indicate an intimate relationship. Under KRE 702, experts may explain injury patterns outside the jury’s common knowledge. Unlike the detective in Ordway, who opined directly on the defendant’s credibility, Dr. Kiefer confined his testimony to a general forensic observation about charged energy in face wounds. Because the testimony was accurate, specialized, and helpful, and did not single out Penn’s guilt, its admission was neither error nor palpable error. The Court further found no reasonable probability of a different verdict absent that testimony, so any error was non-prejudicial.

2.2 Prosecutorial Misconduct and Closing Argument

The Court reviewed comments about “trash pickup day” for palpable error. Prosecutors have wide latitude to draw reasonable inferences and rebut defenses in closing (Mitchell v. Commonwealth, 165 S.W.3d 129). Here, evidence showed Penn’s phone pinged near a landfill on the day of the murder and that over 100 tons of waste arrived that morning. Suggesting Penn used trash pickup to dispose of evidence was a permissible inference attacking the robbery theory. No manifest injustice arose, and the argument fell within the bounds of fair comment.

2.3 Cumulative Error

With no individual errors, there is no cumulative effect compromising trial fairness. The Court reaffirmed that only “harmless” or “non-palpable” errors cannot aggregate to warrant reversal.

3. Impact on Future Cases

This decision provides trial and appellate courts with clear guidance on:

• The limited scope of expert testimony on behavioral inferences—permissible when grounded in specialized training, not focused on a defendant’s guilt.
• The boundaries of prosecutorial argument—permitted to draw inferences from evidence, including investigative leads like cell-phone “pings.”
• The strict application of the palpable error standard—unpreserved errors must be so grave as to threaten due process.

Going forward, practitioners will find in Penn a reaffirmation of Kentucky’s high bar for overturning convictions based on unpreserved claims, especially regarding expert opinion and strategic argument.

Complex Concepts Simplified

• Palpable Error (RCr 10.26): An unpreserved mistake that so undermines the fairness of the trial that it must be corrected, even if not objected to at trial.
• KRE 702 (Expert Testimony): Experts may testify if their specialized knowledge helps the jury, but they may not use anecdotal “class habit” evidence to show a particular defendant acted in conformity.
• Harmless vs. Palpable Error: A harmless error is unlikely to have changed the verdict; a palpable error is so serious it threatens fundamental fairness.
• Prosecutorial Closing Argument: Counsel may comment on evidence and reasonable inferences but may not introduce facts unsupported by the record.

Conclusion

Cocina Penn v. Commonwealth clarifies Kentucky’s approach to unpreserved evidentiary and argument-based challenges under the palpable error standard. The Court’s careful distinction between permissible expert insights and improper opinion, coupled with its protection of a prosecutor’s reasonable inferences in closing, ensures that only truly fundamental mistakes—those undermining due process—will overturn a jury’s verdict. By affirming Penn’s conviction, the Supreme Court reinforces the importance of timely objections at trial and the high threshold for appellate relief on unpreserved issues.