State v. Tyrone Wallace, 892 S.E.2d 310

On Oct. 25, 2015, victim "Mony" disappeared after visiting a Greene Street residence; Andre Frazier was tied up there at gunpoint and later told police Wallace and another person had restrained him.
Remains of Mony were found Nov. 18 near Pea Patch Road on Saint Helena Island; the State presented evidence linking Wallace to the kidnapping, murder, and transportation/attempted burning of the body.
Investigator Dylan Hightower (Solicitor’s office) used historical cell-site location information (CSLI) to create a map showing Wallace’s phone near the Greene Street house, then connecting to towers near Pea Patch Road, and returning—at times corresponding to the crimes.
The trial court held a lengthy pretrial hearing, questioned Hightower extensively about his training (≈72 hours), SLED internship, FBI CAST training, use of CASTViz, and experience analyzing 100+ datasets, and qualified him as an expert under Rule 702 for the limited CSLI testimony.
Wallace appealed the expert-qualification ruling; the Court of Appeals affirmed. The South Carolina Supreme Court granted certiorari solely to review whether the trial court abused its discretion in qualifying Hightower and affirmed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Hightower was qualified under Rule 702 to testify about CSLI mapping	Wallace argued Hightower lacked sufficient training/experience for technical CSLI analysis and that his prosecutor employment made his testimony unreliable	State argued Hightower had formal training, certification (FBI CAST), practical experience (100+ analyses), and would testify only about tower/sector connections (not precise triangulation); employment bears on credibility, not qualification	Court held trial court did not abuse its discretion: Hightower was sufficiently qualified to testify about CSLI interpretation and mapping (limited to tower/sector inferences), and bias was a jury credibility issue

Carpenter v. United States, 138 S. Ct. 2206 (2018) (describes what CSLI is and its variable precision)
State v. Council, 335 S.C. 1 (1999) (sets Rule 702 framework: assistance to trier, qualification, reliability)
State v. Phillips, 430 S.C. 319 (2020) (trial courts must meaningfully exercise gatekeeping discretion on expert testimony)
Morris v. BB&T Corp., 438 S.C. 582 (discusses proper appellate review of a trial court's exercise of discretion)
State v. Hamrick, 426 S.C. 638 (expert qualification requires greater proof for highly technical fields)
State v. Herrera, 425 S.C. 558 (lower levels of expertise may suffice for less complex issues)
State v. Warner, 430 S.C. 76 (Ct. App.) (CSLI expert with extensive FBI training found qualified)
State v. Young, 432 S.C. 535 (Ct. App.) (SLED expert with substantial training/experience found qualified)
State v. Franks, 432 S.C. 58 (Ct. App.) (experienced local officer using GeoTime found qualified)