Science Current Events | Science News | Brightsurf.com
 

Crime scene investigations: Gunshot residue analysis on a single gunpowder particle

April 07, 2008

Scientists in Texas are reporting development of an highly dependable, rapid, and inexpensive new method for identifying the presence of gunshot residue (GSR). The test fills a GSR-detection gap that results from wider use of "green" - lead free - ammunition.

It requires only a single speck of GSR smaller than the period at the end of this sentence and could boost the accuracy of one of the most widely used tests employed at crime scenes involving gunplay.

In a poster presented here today at the 235th national meeting of the American Chemical Society, graduate student Garrett Lee Burleson and his advisor, chemist Jorn Chi Chung Yu, Ph.D., of Sam Houston State University in Huntsville, described their new method. It extracts almost all components of gunpowder residue from particles about 15 times smaller than the width of a human hair, without the use of chemical reagents. After extraction, gas chromatography coupled with a nitrogen phosphorus detector is used to separate and identify the analytes.

"Gunshot residue tests are done in almost every case where a shooting has taken place," Burleson said. "The main focus of our research is to develop a method that will help credibility of gunshot residue evidence in court. You can get results with this test in 30 to 40 minutes with the new test. In addition you only need small amounts of evidence to run the test."

Many of the current methods are susceptible to outside interferences that can produce false positive or false negative results. For example, most tests require the presence of lead for a valid reading, including two of the three mainstays of residue analysis - the sodium rhodizonate test and scanning electron microscopy with energy dispersive x-ray detection.

But Burleson points out that lead is disappearing from ammunition. That potentially toxic metal poses environmental hazards at outdoor firing ranges, where it can leach into groundwater. In response, manufacturers have begun to create safer, environmentally friendly ammunition out of other metals, such as zinc and aluminum alloys.

This recent trend toward lead-free ammunition, Burleson said, has decreased reliability of gun shot residue analysis and created the need for smarter tests to identify more diverse components of residue in gunpowder, including elements like stabilizers and plasticizers, which are added in the powder during the manufacturing process for safety reasons.

"When a gun fires, the gunpowder explodes, producing gases at enormous pressure that propels the bullet out of the barrel of the firearm," explained Burleson, a graduate student in the Master of Science in Forensic Science Program at Sam Houston State University. "Some of the residue from that explosion is deposited on the hands of the shooter and the clothing of the victim." Burleson's new test, which uses a technology called solid phase micro-extraction combined with gas chromatography, focuses on chemical compounds present in that ejected material. "When you have a residue particle, no matter how small, it's going to contain signatures of every element in that powder."

These signatures offer a wider range of detection possibilities compared to traditional methods, he said. Using an alternative method with a scanning electron microscope, for example, a forensic examiner would perform a search for lead, passing up numerous powder constituents in the analysis. "You would just look for the one little piece of metal that might be there, so the analysis could take hours," Burleson said.

"If you're looking for powder, however, there's a lot more of it. You're getting more of the residue to analyze. It makes it a much more efficient method of detection." For example, a distinctive combination of certain chemicals, such as diphenylamine, ethyl centralite and nitrodiphenylamine, is typically found only in explosive mixtures and therefore allows for a simple analysis of gunplay at a crime scene.

In contrast, another traditional test for finding gunshot residue, the modified Griess test, often fails because it lacks such specificity. Its analysis is based on the detection of Nitrogen-based compounds called nitrites, which are gunpowder byproducts. But these compounds are also found elsewhere, leading to possible ambiguity in testing.

"Many chemical cleaners - anything that can be used to take off motor oil or freight dust - will test positive for gunshot residue using the Griess test," Burleson said.

That would make the reading a false positive, which opens the door in court cases for reasonable doubt and possibly incarcerating an innocent person. "The worst thing you can possibly say is, 'There's a chance I'm wrong.' Our preliminary results indicate you can determine the presence of gunshot residue with a high level of confidence."

More efficient testing also would reduce the need for extraneous tests that require time and money while draining resources from a criminal justice system that cannot afford it, Burleson said.

The research was funded by the College of Criminal Justice and Department of Chemistry at Sam Houston State University.

Burleson's test could be used as a preliminary or confirmatory one. "As far as a stand-alone test, it's an excellent, reliable and cheap test to do," he said. "But for the sake of clarity and thoroughness, examiners will usually run multiple tests, such as the sodium rhodizonate test at the crime scene, and they could then confirm the findings with my method."

American Chemical Society


Related Gunshot Residue Current Events and Gunshot Residue News Articles


Real-life CSI: What can investigators really tell from gunshot residue?
The popular TV series "CSI" is fiction, but every day, real-life investigators and forensic scientists collect and analyze evidence to determine what happened at crime scenes.

Facilitating the work of forensic scientists
The University of the Basque Country's (UPV/EHU) METABOLOMIPs group develops analytical methods to help characterize different types of substances, and focuses on the forensic sciences, in particular.

Researchers rest their case: TV consumption predicts opinions about criminal justice system
People who watch forensic and crime dramas on TV are more likely than non-viewers to have a distorted perception of America's criminal justice system, according to new research from Purdue University.
More Gunshot Residue Current Events and Gunshot Residue News Articles

Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques, Third Edition (Practical Aspects of Criminal and Forensic Investigations)

Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques, Third Edition (Practical Aspects of Criminal and Forensic Investigations)
by Vincent J.M. DiMaio M.D. (Author)


Written by the nation's foremost authority on gunshot wounds and forensic techniques as they relate to firearm injuries, this third edition of a bestseller provides critical updates to information on gunshot wounds and the weapons and ammunition used to inflict them. The book describes practical aspects of ballistics, wound ballistics, and the classification of various wounds caused by handguns, rifles, and shotguns. It also explains autopsy techniques and procedures and laboratory analyses relating to weapons and gunshot evidence. A much-needed update after nearly 20 years, the third edition of Gunshot Wounds provides the latest and most thorough information on firearms and best practices for examining firearm-related wounds.

Current Methods in Forensic Gunshot Residue Analysis (Forensicnetbase)

Current Methods in Forensic Gunshot Residue Analysis (Forensicnetbase)
by A. J. Schwoeble (Author), David L. Exline (Author)


With the ever-spreading problem of violent crime in today's society, techniques to assist forensic scientists and other law enforcement personnel have come to the forefront. With improvement in collection methods and analytical tools to conduct more thorough analyses, gunshot residue examination has made a dramatic impact as an area of trace evidence that is essential in the investigation and prosecution of violent crime.

Current Methods in Forensic Gunshot Residue Analysis deals with major areas of gunshot residue analysis such as current and future methods of analysis, collection techniques, interpretation of evidence as well as expert testimony and report writing.

This text is a necessity for any forensic scientist conducting this type of analysis and all other law...

Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques, SECOND EDITION (Practical Aspects of Criminal and Forensic Investigations)

Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques, SECOND EDITION (Practical Aspects of Criminal and Forensic Investigations)
by Vincent J.M. DiMaio M.D. (Author)


Written by the nation's foremost authority on gunshot wounds and forensic techniques as they relate to firearm injuries, Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques, Second Edition provides critical information on gunshot wounds and the weapons and ammunition used to inflict them. The book describes practical aspects of ballistics, wound ballistics, and the classification of various wounds caused by handguns, bang guns, rifles, and shotguns. The final chapters explain autopsy technique and procedure and laboratory analysis relating to weapons and gunshot evidence.

Chemical Analysis of Firearms, Ammunition, and Gunshot Residue (International Forensic Science and Investigation)

Chemical Analysis of Firearms, Ammunition, and Gunshot Residue (International Forensic Science and Investigation)
by James Smyth Wallace (Author)


Firearms and their associated ammunition, spent bullets, and spent cartridge cases provide useful information for identifying suspects, terrorist groups, and the criminal history of a weapon. Unfortunately, despite the numerous detailed books on the physical aspects of firearms, very little has been published on the chemical aspects, and what has been published is sparse and fragmented.
Compiling information from the available literature and supplementing gaps with private communications and personal observations and research, Chemical Analysis of Firearms, Ammunition, and Gunshot Residue summarizes the history of firearms and ammunition as it relates to the development of modern weapons. It details chemical aspects of forensic firearms casework with particular emphasis on the...

Morgue: A Life in Death

Morgue: A Life in Death
by Vincent DiMaio (Author), Ron Franscell (Author)


Forensic science is booming. TV dramas, books and movies have made morgues cool. Complex technology and intricate research can take curdled blood, bone shards, and flakes of skin and turn them into justice. And Vincent Di Maio, MD, son of a famous New York City medical examiner, is one of the lions of forensic science in his own right.  In this clear, gritty, and enthralling narrative, Di Maio himself guides us into the inner sanctum, through the cases that have made him famous, from the exhumation of assassin Lee Harvey Oswald and the racially charged shooting of Florida teen Trayvon Martin, to the unmasking of a serial baby-killer and the mysterious death of troubled genius Vincent van Gogh. Along the way, one of the country's most methodical and intuitive criminal pathologists will...

A Long Time Dead (SOCO Roger Conniston Book 1)

A Long Time Dead (SOCO Roger Conniston Book 1)
by Andrew Barrett


“Forensic evidence is an art like black magic; ‘facts’ are determined by interpretation. Or misinterpretation.”
A Long Time Dead asks is forensic evidence incontrovertible? How would you feel if forensic evidence incorrectly incriminated you? And how would you prove it wrong?
In the world of crime scene investigation, Roger Conniston is one of West Yorkshire Police’s finest. Yet even he has secrets. When forensic evidence implicates him in the death of a young woman, the secrets emerge, and he is damned.
Arrested for murder, Conniston must show the evidence was manipulated and planted. But how can he do that from inside a cell, especially when his prime suspect is a high-ranking police officer, and not even his friends believe him?

A Long Time Dead...

Midnight in the Garden of Good and Evil: A Savannah Story

Midnight in the Garden of Good and Evil: A Savannah Story
by John Berendt (Author)


Shots rang out in Savannah's grandest mansion in the misty,early morning hours of May 2, 1981.  Was it murder or self-defense?  For nearly a decade, the shooting and its aftermath reverberated throughout this hauntingly beautiful city of moss-hung oaks and shaded squares.  John Berendt's sharply observed, suspenseful, and witty narrative reads like a thoroughly engrossing novel, and yet it is a work of nonfiction.  Berendt skillfully interweaves a hugely entertaining first-person account of life in this isolated remnant of the Old South with the unpredictable twists and turns of a landmark murder case.

It is a spellbinding story peopled by a gallery of remarkable characters: the well-bred society ladies of the Married Woman's Card Club; the turbulent young redneck gigolo;...

Practical Analysis and Reconstruction of Shooting Incidents, Second Edition (Practical Aspects of Criminal and Forensic Investigations)

Practical Analysis and Reconstruction of Shooting Incidents, Second Edition (Practical Aspects of Criminal and Forensic Investigations)
by Edward E. Hueske (Author)


Practical Analysis and Reconstruction of Shooting Incidents, Second Edition presents a holistic approach to shooting incident analysis and reconstruction, covering the entire spectrum of related sub-disciplines of forensic science. The book reviews basic firearm design and function, ammunition components, and terminology, explaining what constitutes pertinent evidence and appropriate results relative to autopsies, forensic laboratory analysis, and reenactments. The second edition features numerous additions including: Four new chapters Complete and extensive updates to all 16 original chapters Three case studies contributed by renowned professionals in the field New and revised exercises at the ends of chapters, with answers provided An expanded glossary of terminology Nearly 340 figures...

14th Deadly Sin (Women's Murder Club)

14th Deadly Sin (Women's Murder Club)
by James Patterson (Author), Maxine Paetro (Author)



With San Francisco under siege and everyone a suspect, the Women's Murder Club must risk their lives to save the city-and each other.

With a beautiful baby daughter and a devoted husband, Detective Lindsay Boxer can safely say that her life has never been better. In fact (for a change), things seem to be going well for all the members of the Women's Murder Club as they gather to celebrate San Francisco Medical Examiner Claire Washburn's birthday. But the party is cut short when Lindsay is called to a gruesome crime scene, where a woman has been murdered in broad daylight.

As Lindsay investigates, shocking video footage of another crime surfaces. A video so horrific that it shakes the city to its core. Their faces obscured by masks, the cold-blooded criminals on the...

Terminal Ballistics: A Text and Atlas of Gunshot Wounds

Terminal Ballistics: A Text and Atlas of Gunshot Wounds
by Malcolm J. Dodd (Author)


Terminal Ballistics: A Text and Atlas of Gunshot Wounds is a comprehensive guide that explains the science of forensic ballistics - focusing on the hardware, injury patterns, and forensic techniques associated with gunshot wounds. The text begins by describing the anatomy and design of basic firearms and the fundamental components of ammunition rounds, .22 rimfire, and propellants.

The author presents a variety of gunshot injury patterns, and defines the concept of the pathological range of fire determination. He delineates patterns from injuries sustained by commonly fired rounds, including those acquired after discharge from handguns, high velocity centerfire rifles, shot guns, and black powder weapons. More obscure injuries from air pistols, nail guns, and homemade weapons are...

© 2016 BrightSurf.com