222 A.3d 582
Del. Super. Ct.2019Background
- Defendant Steven Pierce was charged with first-degree murder and related weapon offense for the July 9, 2016 fatal shooting of his girlfriend, Heather Stamper.
- The State sought to introduce Google Wi‑Fi Location Data (location history from an Android device tied to Defendant’s Google account/IMEI) to place Defendant near the victim’s home during the relevant period.
- Defense moved in limine (Daubert) to exclude expert testimony regarding the Google Wi‑Fi Location Data, arguing it is not sufficiently reliable and may confuse the jury.
- The Court held a Daubert hearing; State presented testimony from Andrew Rist (computer/engineer) and Anthony Vega (law‑enforcement cell‑data expert).
- Rist tested Google Wi‑Fi data using a multi‑phone “test rig,” and found Wi‑Fi‑sourced locations generally accurate to about 100 feet in the area of the victim’s home; Vega corroborated Google data with GPS and surveillance video.
Issues
| Issue | State's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Admissibility of expert testimony based on Google Wi‑Fi Location Data under Daubert | Google Wi‑Fi Location Data is reliable, tested, peer‑reviewed, corroborated by GPS/video, and widely used; experts are qualified and testimony will assist jury | Data is novel/unreliable, potentially misleading, and cumulative of GPS/surveillance | DENIED — Court found experts qualified and data sufficiently reliable and helpful |
| Whether Google Wi‑Fi Location Data methodology is testable and tested | Rist’s test rig and two years of data testing show the method is testable and accurate | Challenges to testing gaps and methodology go to weight, not admissibility | HELD admissible; testing requirement satisfied |
| Whether Wi‑Fi geolocation has peer acceptance and known error rates | Wi‑Fi positioning has peer‑reviewed support and marketplace acceptance; corroboration with GPS and video reduces error concerns | Argues potential error sources and temporal gaps undermine reliability | HELD admissible; peer review and corroboration satisfy standards |
| Risk of jury confusion or unfair prejudice (Rule 403/Daubert) | Technology is comprehensible; probative value outweighs risk; any challenges are for cross‑examination | Evidence is duplicative and could mislead or confuse jury | HELD not unduly prejudicial or confusing; admissible with weight for jury to decide |
Key Cases Cited
- Carpenter v. United States, 138 S. Ct. 2206 (2018) (discusses privacy and reliability considerations for location‑related records)
- Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) (establishes gatekeeping standard for admissibility of expert scientific testimony)
- Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) (extends Daubert gatekeeping to nonscientific expert testimony)
- Eskin v. Carden, 842 A.2d 1222 (Del. 2004) (Delaware adoption of Daubert framework)
- Sturgis v. Bayside Health Ass’n Chartered, 942 A.2d 579 (Del. 2007) (factors for assessing expert reliability)
- Rodriguez v. State, 30 A.3d 764 (Del. 2011) (trial court’s role in ensuring expert rigor under Daubert/Kumho)
- Taylor v. State, 23 A.3d 851 (Del. 2011) (recognition of cell‑site/location evidence reliability in criminal matters)