Investigating police officers risk mistaking fireworks particles for gunshot residue, which share similarities, because the chemicals used for fireworks can remain on their hands for eight hours and contaminate a crime scene, a study has found.
Carried out by Matthew Grima, 26, who has just completed a Master’s degree at Teesside University in the UK, the study sheds light on the fact that if police stationed at, say, a village feast move to a firearm-related crime scene, they can potentially transfer fireworks residue from the display site.
New fireworks classification system which should help experts distinguish fireworks particles from gunshot residue, rendering crime investigations less complex and aiding in proving an alibi
Mr Grima’s research shows that, eight hours after a fireworks display, particles remain on the hands, even after sleep and contact with bed sheets.
The study, partly funded by the government’s scholarship scheme, is particularly relevant to Malta because of its many fireworks displays in summer.
But, ironically, it is also a problem abroad, Mr Grima pointed out. In the UK, for example, anyone can purchase consumer-grade fireworks throughout the year.
In a survey of UK police forces, used to assess their practices and strengthen his findings, it transpired that they were not aware that fireworks particles could be mistakenly identified as gunshot residue.
Mr Grima said it was significant that 75 per cent were not aware, and while 25 per cent were, no framework was in place to prevent particle transfer from fireworks displays to the scene of the crime.
None of them have protocols that force their officers to wash their hands and hair, and even shower and change vehicles, after a fireworks display. While these measures would not totally exclude possible contamination, they would minimise it, he said.
Mr Grima will be formally making these proposals, based on the concept of “controllable vulnerability” of gunshot particles vis-à-vis fireworks, to the UK police force and to Malta, where they also apply – displays being so common.
He assumes such awareness would not be high on Malta’s agenda if it is not high in the UK.
In his latest research, related to forensic science, Mr Grima has drawn up a new fireworks classification system which should help experts distinguish fireworks particles from gunshot residue, rendering crime investigations less complex and aiding in proving an alibi.
The fruit of three years of research, the new identification system allows forensic experts to identify fireworks particles “more confidently”, using a list of exclusion markers, typical of these particles.
Mr Grima’s first study had compared gunshot and fireworks residue, confirming similarities between their chemical elements. Moreover, for the first time, particles containing elements used in lead-free ammunition were also identified in fireworks.
The fact that elements previously thought to be found only in gunshot residue were also present in fireworks continued to blur the line between the two, rendering crime investigations tougher and increasing the possibility of misidentification by experts. The study also shed light on another grey area, showing that it was not always the case that the two types of residue had various shapes and sizes.
Experts looking for spherical particles, typical of gunshot residue, now know that these could also be found in fireworks thanks to Mr Grima’s study.