Blood on Sheets: The Juror Investigates
In the Dossett-Leath trial, forensics expert Celia Hartnett testified about blood stains on a pillowcase. Briefly, the essence of the trial is whether a Tennessee man committed suicide with his head lying on his pillow or his wife murdered him while he was sitting up in bed.
Ms. Hartnett testified that her lab received a blood-soaked pillowcase, but crime-scene photos show the pillowcase fairly unstained except with blood spatter, indicating the victim’s head was lying on it when the fatal shot was fired.
I have many questions about how forensic scientists examine blood stains. Earlier I posted a list of abuses of science in court, and abuses numbers 11 and 12 are blood spatter and blood transfer analysis. In the Dossett-Leath case I can’t help but wonder why they didn’t x-ray the pillowcase to reveal the blood spatter stains beneath the second layer of soaked-in blood. Scientists have examined textiles with x-rays for decades (the Shroud of Turin, for example). Art historians routinely x-ray old oil paintings (dry oil and pigment on canvas) to find layers of paint and to reveal the underlying sketches or over-painted, older images (recently a supposed portrait of William Shakespeare was x-rayed).
Frankly, as much as I admired the way Ms. Harnett testified in the Dossett-Leath trial, her failure to x-ray the pillowcase makes me wonder if the underlying blood-spatter stains were truly exculpatory of the defendant. Alternatively, perhaps it’s just another case of the fuzzy junk science involved in blood-spatter analysis.
Another question I have about the analysis of blood on textiles has to do with how much of the textile is subjected to analysis. It has always seemed to me that if blood stains were large, only a small percentage of the blood would be analyzed for blood type and/or DNA. Without some sort of systematic, thorough, spot-analysis technique, it seems that a second person’s blood could be overlooked. The O.J. Simpson murder trial is an example: the blood stains around the bodies of the two victims were huge. While the investigators identified mixtures of blood, I have always wondered whether they actually found all the types of blood present.
(I speculate about this in my story, “The Odds of Death,” in THE EVIL THAT MEN DO [Light Pages, LLC, 2008]. BTW: This is “Read an E-Book Week,” and for the rest of the week this short-story collection is available, free, from www.Smashwords.com. Please download a copy. Fans of forensics may enjoy not only “The Odds of Death,” but also the final three short stories, two of which are satires of criminals who try to outsmart forensics and of forensic experts who think they know it all.)
Categories: Judicious Opinions, Postcard-Sized Mysteries
Quote: "The O.J. Simpson murder trial is an example: the blood stains around the bodies of the two victims were huge. While the investigators identified mixtures of blood, I have always wondered whether they actually found all the types of blood present."
And more interesting, despite the blood soaked gloves and the shoe prints in the blood -- only the tiniest amount of blood was found in Simpson's car. How is that?
I have some ideas--again, this is just my fiction writer's mind at work:
1) blood soaked gloves
Maybe Furman really did pick up one of the blood-soaked gloves at the scene and carry it with him to O.J.'s house that night to plant it there. That would mean the glove was never in the car. Or maybe O.J. really did try to stuff them into his back pocket at the scene and then crammed one far enough down into the pocket to keep the blood off the car seat, while the other dropped out.
2) shoe prints in the blood
Maybe by the time he walked back around the house, through the gate (touch of blood) and back to the alley, most of the blood on the soles of his shoes was wiped off. In addition, if you recall, an FBI hair-and-fiber expert was prohibited from testifying about what he found in the car, because he and the prosecution had failed to produce his notes or something during discovery. He might have found bloody carpet fibers. We'll never know.
However, if your point is that blood-transfer evidence is iffy and highly subjective, then I certainly agree with you there. IMHO: In the O.J. murder trial, blood evidence conclusively proved he had been at the scene of the crime. I repeat--in my opinion. What the prosecution failed to do--or to understand--is that African American jurors are highly suspicious of the police. They concluded that Furman and the other officers could have planted evidence to incriminate O.J., because they "were out to get him." Even I believe this sort of thing happens rather more often that any of us would like to think. The only blood evidence I found compelling was O.J.'s DNA on the sidewalk at the crime scene. I felt that O.J.'s hired-gun experts presented junk-science to the jury about that, and that the prosecution's experts were confusing and inarticulate. I don't blame the jury for any of that.