Forensic expert refutes claim nitrates prove victim fired gun in Acadia case

A retired government forensic analyst on Thursday rejected defence suggestions that the presence of nitrates on the hand of one of three men killed by police in St Andrew in 2013 was proof that he had fired a gun during the incident.

Attorney Hugh Wildman, during cross-examination of the expert witness, suggested that nitrates were “the primary component of gunshot residue” and that their presence on the victim’s hand was “compelling evidence” that the man had gunshot residue.

But the analyst resisted the suggestion.

“I don’t know it as the primary component. I know it as a component,” she said. “What I would say is that it is the primary component of the propellant in the ammunition.”

The witness had testified on Wednesday that no gunshot residue was found on any of the three men- , Mark Allen, Matthew Lee, and Ucliffe Dyer-, who were killed. However, she said a small amount of nitrate was found on one of the samples taken from Dyer.

She had, however, indicated that the presence of nitrate alone, along with the proportion detected, would not be enough to conclude that gunshot residue was present.

Further to that, before completing her evidence-in-chief on Thursday, she indicated that all four components – nitrate, barium, lead, and antimony – would need to be present, or at a minimum, three of them, to conclude that gunshot residue was present.

Additionally, she said that during testing, the quantity of the components is measured and assigned levels: elevated, the highest, at eight and above; intermediate, four to seven; and trace, two or lower.

The witness also testified that nitrates could come from the environment and are found in soil and other substances.

Asked by Wildman whether the nitrate found in soil differed from that associated with gunpowder residue, the witness replied: “No.”

She also indicated that she did not test to determine the specific type of nitrate found in the swab, as she did not see the need to do so.

Further in cross-examination, she accepted that delays in collecting swabs could significantly affect the presence of gunshot residue.

“Delay in obtaining samples, movement of bodies or objects, or washing of the body prior to autopsy will diminish or destroy gunshot residue,” Wildman suggested, citing a medical text during his cross-examination.

“Yes,” the witness responded.

The court heard that the fatal shooting reportedly occurred around midday, andwhile swabs were allegedly taken between 6 p.m. and 7 p.m. that evening.

“That timeframe does fall within three to six hours,” the witness acknowledged after Wildman suggested that there would have been a “rapid decline” in gunshot residue during that period.

The analyst further testified that she did not personally collect all the items from investigators, did not visit the scene, and relied on submission forms accompanying the exhibits sent to the laboratory.