The effect of firearm muzzle gases on the backspatter of blood

TitleThe effect of firearm muzzle gases on the backspatter of blood
Publication TypeJournal Article
Year of Publication2011
AuthorsTaylor MC, Laber TL, Epstein BP, Zamzow DS, Baldwin DP
Journal TitleInternational Journal of Legal Medicine
Date Published09
Type of ArticleArticle
ISBN Number0937-9827
Accession NumberWOS:000293910900001
KeywordsBackspatter, Bloodstain pattern, Gunshot, High-speed video, Shadowgraphy

Injuries caused by gunshots can produce what bloodstain pattern analysts know as "backspatter." Observations about the presence or absence of backspatter on an individual may be used in court as evidence of guilt or innocence. The discharge of three firearms (.22 caliber revolver, .38 caliber revolver, and .308 caliber rifle) and the resulting impact of bullets on a blood source were recorded using high-speed digital video imaging. Blood droplets, firearm muzzle gases, and ballistic shock waves were visualized using standard reflected light and shadowgraphy imaging techniques. A significant interaction between air currents, muzzle gases, and particulate material emanating from the firearms upon discharge with backspattered blood was observed. Blood droplets, initially spattered back toward the firearm and the shooter, were observed to change direction under the influence of firearm-induced air currents and were blown forward toward and beyond their original source location. Implications for experts testifying in court and for bloodstain pattern instructors are discussed.

Alternate JournalInt. J. Legal Med.