Paul Greer

Paul Greer testified for the State as a SLED firearms and tool-mark examiner. During an admissibility hearing, he described his scientific education, examiner training, proficiency testing, comparison methods, laboratory accreditation, and verification procedures. Judge Newman admitted his report and opinions, ruling that the defense's methodological criticisms concerned cross-examination and evidentiary weight rather than exclusion.

Before the jury, Greer explained his examination of submitted firearms, shotshells, and cartridge cases. He concluded that two shotshells recovered near the kennel feed or storage room were fired by the same firearm, but he could not determine that the submitted camouflage Benelli shotgun fired them. He also identified six submitted cartridge cases as having been fired by the tested .300 Blackout rifle, while other firearm comparisons discussed during cross-examination remained inconclusive.

Greer separately found that specified .300 Blackout cases recovered near Margaret Murdaugh, the house, and a shooting area bore marks showing that they had been loaded into, extracted from, and ejected from the same firearm. He acknowledged that a firearm can produce cycling marks without firing and that he could not determine when the cycling occurred. He also described a feeding failure during testing of the submitted rifle and said he did not investigate its cause further.

The defense challenged the absence of a numerical matching threshold, the subjective judgment involved in pattern comparison, the research available to Greer, and the lack of an independent report from the second examiner. Greer acknowledged published concerns about reproducibility, study design, and foundational validity while defending the discipline through trained microscopic comparison, research, proficiency testing, laboratory controls, and blind verification. On redirect, he explained that an inconclusive result leaves both the examined firearm and other firearms with similar characteristics as possible sources, while maintaining his narrower conclusion that specified cases shared a prior cycling history.