Justice for Athena: Forensic Revelations and a Mother’s Agony Define Day 7 of Tanner Horner’s Capital Murder Trial

DECATUR, TEXAS — The air inside the Wise County courtroom remained heavy with the scent of grief and the clinical coldness of forensic science on Thursday, April 16, 2026. As the capital murder trial of Tanner Horner entered its seventh day, the proceedings offered a jarring juxtaposition: the meticulous, dispᴀssionate analysis of DNA evidence followed by the raw, soul-crushing testimony of a mother forced to bury her seven-year-old child.

Tanner Horner, the former FedEx driver who has already pleaded guilty to the November 2022 kidnapping and murder of Athena Strand, sat largely expressionless as the state moved closer to its goal of securing the death penalty. While his guilt is no longer in question, the jury must now weigh the sheer brutality of the crime against the forensic trail he left behind and the immeasurable loss suffered by those who loved the “vibrant” little girl.

The DNA Trail: Science in the Search for Truth

The morning session was dominated by the technical testimony of Kristen Cossota, a forensic scientist with the Texas Department of Public Safety (DPS) Crime Lab in Garland. Cossota, an expert with over a decade of experience, walked the jury through the exhaustive processing of the Sєxual ᴀssault kit and physical evidence collected shortly after Athena’s body was recovered in late 2022.

Cossota emphasized the urgency of the investigation, noting that under Texas law, Sєxual ᴀssault kits are prioritized. The swabs taken from Athena—oral, anal, and vaginal—were processed within a 90-day window to ensure the integrity of any potential male DNA.

Understanding the Genetic Blueprint

Cossota explained that her lab utilized two distinct types of DNA testing to build a profile of the crime:

    Autosomal STR Testing: This method analyzes DNA inherited from both parents. It is the “gold standard” for identifying individuals. According to Cossota, this test yielded “strong results” on several clothing stains. The data suggested a near-certainty that both Tanner Horner and Athena Strand’s DNA were present on the same items, physically linking the defendant to the victim’s clothing.
    Y-STR Testing: This test focuses exclusively on the Y-chromosome, which is pᴀssed down from father to son. It is particularly useful in cases of Sєxual ᴀssault where male DNA may be present in very small amounts or mixed with an abundance of female DNA.

The Complications of the Evidence

However, the forensic trail was not without its complexities. On a vaginal swab, the Autosomal STR test did not include Horner as a contributor. Instead, it suggested the presence of Athena’s DNA and that of another “unknown person.”

Conversely, the Y-STR testing on the oral, anal, and vaginal swabs provided a different perspective. While the samples were limited, Cossota testified that Horner “could not be ruled out” as a contributor. Specifically, a partial male profile found on the oral swab was consistent with Horner’s paternal lineage.

Cossota was careful to clarify the linguistic nuances of forensic reporting for the jury. “In our field, we rarely use the word ‘match’ because DNA mixtures are complex,” she explained. Instead, labs use the terms “excluded” (meaning the person is definitely not the source) or “cannot be excluded” (meaning they remain a possible contributor). While Horner was excluded from one specific swab, the totality of the DNA evidence on Athena’s clothing and other samples created a devastating link between the driver and the child.