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Firearms examiner links multiple spent casings to prosecution pistol; defense presses chain‑of‑custody gaps
Summary
In the Marco Moreno Vasquez trial, a Bexar County firearms examiner testified that several spent cartridge casings matched a pistol in evidence, while defense counsel argued the lab and deputies cannot account for all handling and openings of evidence packaging.
David Pendleton, a firearms examiner at the Bexar County criminal investigation laboratory, told jurors he test-fired the pistol entered as State Exhibit 2‑11A and compared the result to recovered cartridge cases, concluding "they were fired in this pistol," the examiner said. Pendleton described the lab’s routine: test-firing, producing known standards, and using a comparison microscope to compare class and individual markings.
Defense counsel sought to undercut that conclusion by focusing on the paperwork and packaging. A deputy who initially handled the items testified she separated ammunition from the magazine and placed items into State Exhibit boxes but acknowledged she did not initial the envelope containing loose rounds and could not attest that the ammunition now before the jury remained unchanged from the time she submitted it. Defense counsel argued that multiple people and lab sections had touched and reopened the evidence box over time, and moved to exclude a package labeled 2‑11C for lack of a continuous, personal chain of custody. The judge sustained the defense’s predicate objection until the state presented additional lab testimony, and then admitted 2‑11C after Pendleton described his receipt, inventory markings, and analysis linking the package to the lab’s case number.
Pendleton also described the crime-lab intake and evidence-tracking procedures: an agency submission number ties items to a lab case number (here recorded as 23‑01349), analysts assign internal item numbers when they open and inventory submissions, and examiners place initials and dates on interior packaging. On cross-examination, Pendleton acknowledged that items had been sealed and unsealed multiple times and that handwriting and stamps from several people (evidence receiving staff, analysts in other sections) appeared on the box. He said he could not personally vouch for every handling event, and that determining who touched the box on every occasion requires consulting the chain-of-custody record.
Pendleton emphasized the limited scope of his scientific opinion: matching spent casings to a firearm is a laboratory determination about source, not a reconstruction of how or by whom the firearm was fired. ‘‘We’re not involved in the investigation,’’ he said, describing the lab’s role as analyzing submitted evidence and not determining events or authorship. Defense counsel used that limitation to argue the matching opinion does not, by itself, prove the defendant fired the gun.
The court admitted the challenged exhibits after the lab testimony. Attorneys completed testimony for the morning session and the jury was excused for a lunch break; the trial resumed after evidence and cross-examination had established the lab’s procedures and the dispute over packaging and handling.
