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Court hears DNA analyst: mixed results tie both missing girl and defendant to different items
Summary
A forensic DNA analyst testified to laboratory findings on clothing and items recovered in the investigation: some swabs produced profiles that very strongly match the missing girl, others produced mixed profiles that include or exclude the defendant; the analyst stressed limits on transfer and timing.
A forensic DNA analyst testified in 36th District Court about laboratory testing on multiple items recovered in the investigation, saying some samples yielded profiles that very strongly matched the missing girl’s known sample while other items produced mixed results that either included or excluded Jarvis Butts.
The lab analyst (government forensic laboratory) told the court she examined swabs and cuttings including earbuds, fabric mattress‑pad stains, a plastic mattress‑cover piece, shower‑drain swabs, two black‑hoodie stain swabs, and pink bodysuit/onesie swabs. She also reported running the defendant’s buccal (cheek) swab as a known reference and a blood card for the child.
On the plastic mattress‑cover piece the analyst said a statistical mixture analysis strongly supported that the sample derived from four unrelated individuals and that Jarvis Butts was excluded — the software returned a result she summarized as a “very strong” statistical indication that the defendant did not contribute to that specific sample. For the shower‑drain swabs the analyst testified the result was similarly weighted away from the defendant (she described it as moderate support that he was not a contributor).
By contrast, the analyst said one of the black‑hoodie stain swabs showed genetic results that provide "moderate support" that Jarvis Butts contributed to that sample: the comparison returned a likelihood ratio the analyst summarized in court to indicate moderate support that the defendant was a contributor. The analyst also testified the same hoodie swabs included very strong statistical support that the child (identified in lab submissions as Naziah/Neziah Harris) contributed to other stain swabs from the hoodie and the pink bodysuit; for some pink‑bodysuit items the analyst reported “very strong support” for contribution by the child and in one pink‑bodysuit sample she said Jarvis Butts was more likely not a contributor.
The analyst explained the laboratory’s interpretation process and emphasized limitations: DNA testing cannot date when DNA was deposited on an item and cannot by itself determine the mechanism of deposition (primary deposit from direct contact versus secondary transfer). She described using mixture‑interpretation software (STRmix) to compare evidence mixtures to reference samples and reported likelihood ratios for competing hypotheses (for example, “originated from X plus unrelateds” versus “originated from unrelated individuals”).
Why it matters: The contrasting results — exclusion on some items and moderate/strong inclusion on others — mean the DNA record in court is complex. The analyst’s testimony provides statistical measures that both prosecution and defense can use in argument, but the witness also gave repeated cautions that presence of DNA alone does not establish timing or how DNA got onto an item.
