## Facts

- Sandra L. Wilbur-Bobb spent part of the night drinking with friends, first at a bar and later at a party.
- In the early morning hours, Wilbur-Bobb drove her Jeep with three friends to go “four wheeling” on narrow roads.
- At approximately 5:30 a.m., Wilbur-Bobb drove the Jeep off the road at roughly 15–20 miles per hour.
- The Jeep rolled upside down into waist-deep swamp water, and one passenger drowned.
- The State charged Wilbur-Bobb with vehicular homicide; the central disputed question at trial was whether she was intoxicated at the time of the crash.
- Police arranged a blood draw at 9:41 a.m. The tested blood-alcohol concentration (BAC) was 0.05 at the time of the draw, below the 0.08 per se limit.
- The State called toxicologist Estuardo Miranda, who used retrograde extrapolation to estimate that Wilbur-Bobb’s BAC at the time of the crash was between 0.092 and 0.156.
- Officers testified they observed signs of intoxication; one officer testified Wilbur-Bobb admitted having about six drinks and said she believed alcohol affected her driving.
- Passengers testified they were intoxicated but did not think Wilbur-Bobb was intoxicated.
- The jury found Wilbur-Bobb guilty, and the trial court imposed a sentence of 31 months. Wilbur-Bobb appealed, challenging admission of the blood evidence and Miranda’s testimony.

## Issues

1. Did the State lay a sufficient foundation to admit the blood-test result by making a prima facie showing that the blood sample was properly preserved with an enzyme-inhibiting chemical such as sodium fluoride?
2. Did the trial court err by admitting retrograde-extrapolation testimony without a Frye hearing on general scientific acceptance, where the defense did not raise Frye in the trial court?

## Decision

- The Court of Appeals affirmed Wilbur-Bobb’s vehicular-homicide conviction.
- The State made a prima facie showing that the blood sample was properly preserved: a photograph showed the vials were labeled as containing sodium fluoride, and testimony established chain of custody.
- The court rejected the Frye argument because it was not raised at trial; the defense’s objections focused on foundation and the witness’s qualifications, not on whether the method lacked general acceptance.
- The court also noted that retrograde extrapolation is a routinely used forensic method, and disputes about the assumptions used in a particular calculation are for the jury to consider in weighing the testimony.

## Legal Principles

- To admit blood-alcohol test results, the State must present enough evidence to make a prima facie showing that the sample tested was preserved with an enzyme poison such as sodium fluoride; remaining claims of contamination or handling problems generally affect weight, not admissibility.
- Photographic evidence of vial labeling, combined with chain-of-custody testimony, can satisfy the prima facie foundation requirement for preservation.
- A Frye challenge to scientific evidence must be raised in the trial court; if a party does not invoke Frye or claim lack of general acceptance below, the claim is ordinarily waived on appeal.
- Retrograde extrapolation is treated as a recognized forensic technique; arguments targeting an analyst’s inputs, assumptions, or case-specific application usually go to the persuasiveness of the testimony rather than whether it may be heard by the jury.

## Conclusion

The court affirmed Wilbur-Bobb’s conviction because the State established an adequate foundation for the blood-test evidence through vial labeling and chain-of-custody proof, and because Wilbur-Bobb did not preserve a Frye objection to retrograde extrapolation; any remaining disputes about the toxicologist’s assumptions and calculations were matters for cross-examination and jury weight.


State v. Wilbur-Bobb, 141 P.3d 665 (2006)