Blood Is the Ink, Crime Is the Story
Blood flies, and leaves a tale. But it takes an expert like Paulette Sutton to sort truth from fiction in spatter language

 

By Jessica Snyder Sachs


Courtesy Dr. Steven A. Symes


Aided by binocular magnifiers (on forehead), Sutton examines evidence from a Tennessee case in which a woman was beaten to death in a junkyard.

Sutton's more thorough search of the same death scene turned up a bloodied table leg and bedpost. The impact angle of the blood spatter on the bedpost aligned with the victim's face in a way that suggested the post had been used as a weapon before being dropped to the floor, where it caught flying blood from a subsequent beating with the table leg.

Even more dangerous than oversimplification, says Sutton, are the many instances when blood-spatter experts go too far, claiming they can describe exactly how a murder unfolded -- with moment-by-moment, freeze-frame accuracy. Sutton scoffs at criminalists who claim spatter can tell them whether an assailant is right- or left-handed. "When it comes to beating or stabbing someone to death, we all become switch-hitters," she explains.

Reading blood evidence in a narrow, absolutist way is a temptation that's hard to resist. "There's a frustration level," Sutton says. "You so want to know what the hell happened. So your mind fills in the blanks. But if you're a good scientist, you know there are probably alternative explanations, and it's our job to find them all."

Sutton describes bloodstain-pattern analysis as one part common sense to one part physics and math. A drop of blood, once launched in motion, follows a parabolic (arcing) path until it strikes a surface, where it produces an elongated stain. With some straightforward trigonometry, the ratio of the stain's width to its length reveals the blood drop's angle of impact. The angle of impact, in turn, allows the analyst to draw a line back to a projected point of origin. This is the "projected point" that crime scene investigators plot when they run strings or shine laser lights away from multiple bloodstains to a place where the lines intersect. Because a straight line is being used to approximate a parabolic flight path, the bloodstain analyst knows that the actual point of origin has to be at or below the projected point, never above.

In Sutton's view, this dividing line between the possible and impossible illustrates the true value of bloodstain analysis -- it can expose a lie, corroborate an honest accounting of events, and suggest questions.

"There's nothing I love more than feeding questions to investigators," says Sutton. "We can lead them, suggest 'Why don't you ask him this and that?' "

The answers can surprise even a veteran. In one of her most disturbing cases, Sutton was approached, in 1999, by defense attorneys representing Shawn Allen Berry, the last of the three men convicted of the infamous, racially motivated Texas dragging murder of James Byrd Jr. The defense hoped that Sutton could corroborate Berry's claim that he did not participate in Byrd's murder but had retreated to the cab of his truck after being threatened by his roommates for trying to stop them. The badly beaten Byrd was chained to and dragged behind Berry's pickup for three miles, until dismembered. Berry explained the bloodstains on his jeans by saying he got them on the afternoon following the murder, when he helped one of his roommates wash off the blood-drenched truck and chain at Jasper's Splish-Splash Car Wash.

"I figured I'd just show this guy was lying and be done with it," Sutton admits. She bought a pile of color-matched, secondhand jeans and spattered them with blood -- first with a rat-trap device designed to replicate the spatter produced by a beating, then with a spray-mist bottle to simulate higher-velocity droplets, such as those spewed from the mouth of a beating victim choking on his own blood. Finally, she attempted to scrub out the blood to see if the large, relatively light bloodstains on Berry's clothes could have resulted from his attempts to wash off the evidence. "Instead, I found the reverse, that if blood dries on clothes and you then wet it, you get a darker ring around the outside of the stain."

Next Sutton took more jeans, a heavy length of chain, and a bucket of blood to a local car wash. Sutton hung the pants, their legs stuffed with rolls of paper towel wrapped in plastic, from a floor-mat rack; laid out the bloodied chain in front of them; and hit it with a stream of water from a high-pressure water wand. The resulting back-spatter produced stains that were the same size and intensity as those found on Berry's pants.

Still skeptical, Sutton shot back questions for the defense attorney to ask his client regarding who did what at the car wash. That's the beauty of bloodstain evidence, says Sutton. "If he was lying, there would be no way for him to know the 'right' answers."

Berry replied that he had washed off the outside of the truck while roommate Bill King threw away beer cans and pulled the bloodied chain from the flatbed; that he then handed the water wand to King to blast the chain. How close was he to the chain and how much blood was on it? Sutton wanted to know. So close and so much he could smell it, came the reply.

"All his answers matched what I saw," says Sutton. With mixed emotions, she appeared as a witness for the defense, giving testimony that may have played a large role in the jury sentencing Berry to life in prison, as opposed to the death penalties his two roommates received.


Sutton's more thorough search of the same death scene turned up a bloodied table leg and bedpost. The impact angle of the blood spatter on the bedpost aligned with the victim's face in a way that suggested the post had been used as a weapon before being dropped to the floor, where it caught flying blood from a subsequent beating with the table leg.

Even more dangerous than oversimplification, says Sutton, are the many instances when blood-spatter experts go too far, claiming they can describe exactly how a murder unfolded -- with moment-by-moment, freeze-frame accuracy. Sutton scoffs at criminalists who claim spatter can tell them whether an assailant is right- or left-handed. "When it comes to beating or stabbing someone to death, we all become switch-hitters," she explains.

Reading blood evidence in a narrow, absolutist way is a temptation that's hard to resist. "There's a frustration level," Sutton says. "You so want to know what the hell happened. So your mind fills in the blanks. But if you're a good scientist, you know there are probably alternative explanations, and it's our job to find them all."

Sutton describes bloodstain-pattern analysis as one part common sense to one part physics and math. A drop of blood, once launched in motion, follows a parabolic (arcing) path until it strikes a surface, where it produces an elongated stain. With some straightforward trigonometry, the ratio of the stain's width to its length reveals the blood drop's angle of impact. The angle of impact, in turn, allows the analyst to draw a line back to a projected point of origin. This is the "projected point" that crime scene investigators plot when they run strings or shine laser lights away from multiple bloodstains to a place where the lines intersect. Because a straight line is being used to approximate a parabolic flight path, the bloodstain analyst knows that the actual point of origin has to be at or below the projected point, never above.

In Sutton's view, this dividing line between the possible and impossible illustrates the true value of bloodstain analysis -- it can expose a lie, corroborate an honest accounting of events, and suggest questions.

"There's nothing I love more than feeding questions to investigators," says Sutton. "We can lead them, suggest 'Why don't you ask him this and that?' "

The answers can surprise even a veteran. In one of her most disturbing cases, Sutton was approached, in 1999, by defense attorneys representing Shawn Allen Berry, the last of the three men convicted of the infamous, racially motivated Texas dragging murder of James Byrd Jr. The defense hoped that Sutton could corroborate Berry's claim that he did not participate in Byrd's murder but had retreated to the cab of his truck after being threatened by his roommates for trying to stop them. The badly beaten Byrd was chained to and dragged behind Berry's pickup for three miles, until dismembered. Berry explained the bloodstains on his jeans by saying he got them on the afternoon following the murder, when he helped one of his roommates wash off the blood-drenched truck and chain at Jasper's Splish-Splash Car Wash.

"I figured I'd just show this guy was lying and be done with it," Sutton admits. She bought a pile of color-matched, secondhand jeans and spattered them with blood -- first with a rat-trap device designed to replicate the spatter produced by a beating, then with a spray-mist bottle to simulate higher-velocity droplets, such as those spewed from the mouth of a beating victim choking on his own blood. Finally, she attempted to scrub out the blood to see if the large, relatively light bloodstains on Berry's clothes could have resulted from his attempts to wash off the evidence. "Instead, I found the reverse, that if blood dries on clothes and you then wet it, you get a darker ring around the outside of the stain."

Next Sutton took more jeans, a heavy length of chain, and a bucket of blood to a local car wash. Sutton hung the pants, their legs stuffed with rolls of paper towel wrapped in plastic, from a floor-mat rack; laid out the bloodied chain in front of them; and hit it with a stream of water from a high-pressure water wand. The resulting back-spatter produced stains that were the same size and intensity as those found on Berry's pants.

Still skeptical, Sutton shot back questions for the defense attorney to ask his client regarding who did what at the car wash. That's the beauty of bloodstain evidence, says Sutton. "If he was lying, there would be no way for him to know the 'right' answers."

Berry replied that he had washed off the outside of the truck while roommate Bill King threw away beer cans and pulled the bloodied chain from the flatbed; that he then handed the water wand to King to blast the chain. How close was he to the chain and how much blood was on it? Sutton wanted to know. So close and so much he could smell it, came the reply.

"All his answers matched what I saw," says Sutton. With mixed emotions, she appeared as a witness for the defense, giving testimony that may have played a large role in the jury sentencing Berry to life in prison, as opposed to the death penalties his two roommates received