Blood spatter experts discover how shooters keep themselves clean

By James Gamble via SWNS

Dexter-style violent crime experts believe loose spatters of shooting victims' blood change direction in mid-air due to "gases" released by fired weapons.

They say it could explain the mystery of how some short-range shooters keep their clothes completely clean.

American scientists believe large droplets of blood split in mid-air and change direction due to the effect of gases released from the muzzle of a smoking gun after a shooting.

These gases can so dramatically change the direction of blood droplets that some can even be found behind the bodies of shooting victims.

The research team, from the University of Illinois Chicago and Iowa State University, believe their discovery could aid crime-scene analysts like the main character in popular crime series "Dexter" in deciphering the circumstances of a shooting.

The team also plan to soon turn their attention to the similarly gory subject of brain tissue splatters from shootings.

The study team modeled the behavior of blood drops using "secondary atomization" to examine how the phenomenon affects crime scenes.

Secondary atomization refers to the blood spatters which break away from bigger droplets of blood in mid-air.

Lead study author Professor Alexander Yarin, from the University of Illinois, explained: "Primary atomization of blood is caused by a gunshot - a bullet.

"It results in multiple drops being spattered in the air.

"Some of these drops are big enough to be significantly distorted and torn apart by the air drag forces acting on a drop in flight.

"Smaller droplets arise during this process, which is called secondary atomization."

The research team examined different starting droplet sizes and confirmed their model with experiments; discovering that secondary atomization was both predictable and significant.

The scientists discovered that smaller, secondary droplets of blood were susceptible to being "swept up" by gases released by a discharged gun - changing their direction and turning them towards the shooting victim.

This could, the researchers say, mislead crime-scene investigators analyzing where the weapon was shot from and lead to false conclusions.

It may also explain why some close-range shooters leave a crime scene where they have shot someone directly in front of them without the tiniest of blood spatters on their clothes.

The most high-profile example of this phenomenon occurring was when celebrated music producer Phil Spector shot and killed American actress Lana Clarkson in his home in Alhambra, Calif., in February 2003.

Despite being convicted of murdering 40-year-old Clarkson in 2009, Spector, who later died in prison, emerged with his outfit remarkably clean - despite prosecutors alleging he had held a Revolver in her mouth as he shot her.

Prof. Yarin added that blood droplets can be so deflected by the fired gun's gases that some can even incredibly land behind a shot victim.

He said: "Muzzle gases form a turbulent vortex ring which moves toward a victim from a shooter and pushes the blood droplets from the shooter back to the victim.

"Droplets are also deflected aside, and our predictions showed that some can even land behind the victim, even though initially they were moving from the victim toward the shooter.

"The results reveal the usefulness of multiphase flow fluid mechanics for the forensic discipline of back spatter analysis.

"Hopefully, code based on the present results would be used in future crime scene investigations."

The cross-university team behind the study, which was published in the journal Physics of Fluids, hopes to further analyze short-range shootings by studying the spatter of brain tissue, which could help distinguish between a suicide and a staged murder.