Rain Did Not Wash Away Defendant’s Blood and DNA in Trayvon Martin Murder Case

January 6, 2013

Absence of evidence is not evidence of absence.

The defendant claims that Trayvon Martin punched him repeatedly in the face (24 times) after breaking his nose and knocking him to the ground with a sucker punch. He told the police that Trayvon straddled him as he lay on his back and rained down blow after blow striking him in the nose and face approximately 24 times. When he started screaming for help, Trayvon then grabbed his head and started slamming it into a cement sidewalk until he thought his head would explode. Then Trayvon pinched his nose and covered his mouth to silence his screams for help and suffocate him to death. He said he suddenly remembered that he had a gun concealed in a holster inside the waistband of his pants behind his right hip when he thought he felt Trayvon reaching for it, so he pulled it out, extended his right arm and shot Trayvon to death.

There are a multitude of problems with this story, not the least of which is the absence of any significant wounds that one would expect to see from such a beating. We have examined and discussed photos of the defendant’s wounds taken by a professional photographer at the police station several hours after the shooting and concluded that his minor wounds are not consistent with his story. We have several medical professionals commenting on this blog who have treated patients who were beaten as badly as the defendant claimed he was beaten and their wounds were far more serious than the defendant’s and required medical treatment. The defendant was treated at the scene and declined multiple offers to transport him to the ER for treatment. The photos taken at the police department do not support his claim that his nose was broken. In fact, we have not found any persuasive evidence that Trayvon ever struck the defendant.

For example, if the defendant’s story were true, we would expect that the crime lab would have detected the presence of the defendant’s blood and DNA on the lower sleeves and cuffs of his two sweatshirts and his fingernail cuttings obtained by the Assistant Medical Examiner at the autopsy. The crime lab did not detect the presence of blood on the lower sleeves and cuffs of Trayvon’s sweatshirts and the only DNA detected in the fingernail cuttings excluded the defendant and was was consistent with Trayvon Martin.

The defendant’s supporters contend that no blood was detected on the cuffs and lower sleeves of Trayvon Martin’s two sweatshirts because the rain had washed away all of the defendant’s blood and the scrapings from only one fingernail were tested. They also claim that no blood was discovered on Trayvon’s hands because Trayvon covered them with plastic bags before he assaulted the defendant.

Let’s deal with the last claim first because it is the most ridiculous. Police routinely bag the hands of homicide victims to preserve trace evidence and that is what they did to Trayvon’s hands.

They also complain that Trayvon’s hands were not swabbed, but that is not surprising since the standard practice is to cut a homicide victim’s fingernails and examine them for trace evidence. Forensic scientists do this because trace evidence can transfer from a victim’s hands to another person, surface or fall off. Trace evidence, particularly blood and DNA gets trapped under fingernails and that is why fingernail cuttings are the preferred location to check for trace evidence.

They soak the fingernail cuttings in a solution of purified water overnight and spin it out in a centrifuge to obtain all of the cellular debris present. Then they examine the debris under a microscope. If they find intact cells, the extract the DNA and type it. They do not scrape one fingernail and throw the rest away. Whoever conjured up that explanation has absolutely no idea what they are talking about. It’s probably the same person who said Trayvon wrapped his hands in plastic bags before assaulting the defendant.

Pathetic and laughable nonsense.

What about the claim that rain washed away the blood and DNA?

That claim is almost, if not quite as ridiculous, because we are discussing whether the rain would wash away all blood present on fabric leaving no detectable trace amount. To understand why the rain would not wash away any detectable amount of blood, let us take a look at presumptive tests for blood and failed efforts to remove all detectable trace amounts of blood invisible to the human eye.

Experience has shown that it’s virtually impossible to clean-up blood spatter at a crime scene so that no DNA can be detected. And that is after using water, solvents, cleaning fluids and other assorted chemicals in multiple washings to remove all visible traces of blood. Even though the human eye cannot see trace amounts of blood residue, luminol will detect it. Luminol is so sensitive that it can detect the presence of blood in serial dilutions down to 1:100,000. If luminol can detect it, PCR testing certainly will type the DNA present.

Other chemicals used in presumptive testing for the presence of blood are leuchomalachite green, phenolphthalein, Hemastixs, Hemident, and Bluestarr. All are as equally sensitive to blood as Luminol except for leuchomalachite green (1:10,000). For more information, please read this Technical Note in the Journal of Forensic Science, published in 2006. JFS is a peer reviewed professional journal.

The defendant’s supporters do not realize that a complete DNA profile can be developed from the DNA contained in a single white blood cell by using the STR/PCR process (red blood cells do not have a nucleus). In practice, they require more than a single cell to avoid copying a contaminant DNA introduced extraneously into the testing process, but they do not need very much sample.

In the mid 80s, Dr. Kary Mullis developed a new DNA typing system that involved using chemicals and bacteria present in high temperature hot springs to mimmick cellular division and create more DNA, or PCR product to type. PCR is short for the polymerase chain reaction. The process can produce millions of copies of specific sequences of genetic material or loci called STR’s (short tandem repeats) The FBI Crime Lab later standardized the DNA extraction and typing process. By the end of the 90s, all public and private crime labs were using the same kit to type DNA and that is what the Florida Crime Lab did in this case.

In 1993, Dr. Mullis was awarded the Nobel Prize in Chemistry for his discovery.

Therefore, the argument that rain washed away even invisible trace amounts of blood and DNA is ridiculous and not supported in any of the peer reviewed literature.

For more information on Dr. Mullis, please visit his website and Wikipedia. He is a genius, avid surfer and fascinating character, even if some of his political views and opinions are a bit odd.


The Two Photographs of the Defendant’s Head Damage the Defense

December 17, 2012

Monday, December 17, 2012

After reviewing and considering the remarks by Zhickel, Grbsb, Jun and Whonoze (AKA: Treeslaw), I am going to put on my judge’s robe and issue the following ruling:

I find that neither photograph was altered and, therefore, both photographs are authentic and admissible at trial.

This is not a bad result for the State, as you will soon see.

In effect and by design, because I set it up this way, we have had our own internet version of a battle-of-experts pretrial hearing regarding the admissibility of the two digital photographs taken at the scene of the homicide by Officer Wagner (face) and the neighbor named Jon (back of the head).

The legal issue was whether the photos were authentic (i.e., originals or authentic reproductions) or fraudulent reproductions (i.e., altered).

Zhickle (nice to see your fonts again) and Grbsb in effect testified as experts for the defense while Jun and Whonoze testified as experts for the State.

There has to be a winner and on balance I decided for the defense because giving them what they want on this issue does not hurt the State’s case and I did not want to give them an appellate issue that might result in reversing the defendant’s conviction.

In other words, I am thinking strategically, or big picture, rather than focusing on the relative merits of each argument.

I predict Judge Nelson will reach the same conclusion for the same reason.

Just as I would do, I predict she will permit the prosecution to use their experts to acknowledge the distortions in the photos and explain why they are present, just as our four experts did. Such factors will go to the weight, or value of the evidence, rather than its admissibility.

The jury will decide how much weight to give to those photos. The greater the distortion, the less weight they are likely to be given.

The photos taken at the station house also will be admitted. Those photos together with expert testimony from one or more trauma surgeons should establish to a reasonable medical certainty that the defendant’s injuries, including his claimed but unverified “broken nose” were minor and inconsistent with the defendant’s narrative claiming how he got them.

The absence of any detectable trace of blood on the cuffs and lower sleeves of Trayvon Martin’s two sweatshirts and the absence of the defendant’s DNA in Trayvon Martin’s fingernail clippings also do not support the defendant’s narrative, as one would expect detectable amounts of the defendant’s blood and DNA in both areas. That is, despite the rain, detectable amounts of blood and DNA would have been present, if the defendant’s narrative were true.

In addition, the pattern of blood flow as depicted in the photo taken at the scene, before an EMT cleaned his head, shows blood flowing in a downward direction toward and curling around the lower end of his ears, which does not support the defendant’s claim that he was lying on his back. Instead, it shows that his head was upright and leaning forward, which is consistent with the defendant straddling Trayvon Martin, as several witnesses described him doing (Selma and the teacher).

These photos do not help the defense case. Considered together with the physical evidence, they appear to not only rule out the possibility that the defendant was reasonably in fear of imminent death or serious bodily injury, they also appear to rule out Trayvon Martin as the person who caused those wounds.

Given some minor scratches to his face, it appears more likely that the defendant ran into a tree branch in the dark bumping his nose and fell down bumping his head on some object, possibly a sprinkler head or cover, or possibly the edge of the cement sidewalk or a sign. Whatever caused them, it was not likely to have been Trayvon because there is no evidence that Trayvon Martin hit the defendant.

Even if he did hit him, I think the jury will find that he was legally justified to do so in self-defense because the defendant followed him first in his vehicle and then on foot into a dark area where he confronted and attempted to detain him without ever identifying himself, contrary to the police dispatcher’s admonition and the Neighborhood Watch rules.

I hope this exercise was helpful to a better understanding of hearings on motions in limine, battles between experts and the strategic considerations that inform judicial thinking.

Thanks to all of you for participating and please give me some feedback regarding whether this worked for you as a learning experience.


What Does Zimmerman’s Blood Tell Us?

September 23, 2012

We need to focus today on the information available to us regarding the fatal shot in order to determine as best we can the respective positions of Zimmerman and Martin when Zimmerman fired the fatal shot.

As we do so, we have to keep in mind that there are two bloodstains on Martin’s shirt, which he was wearing under the hooded sweatshirt. DNA analyst Anthony Gorgogne has identified Zimmerman as the source of Stain A. He also concluded that Stain D is a mixed sample of Zimmerman and Martin.

In yesterday’s article on the DNA results, I mentioned that those are the only bloodstains on Martin’s clothing that contain Zimmerman’s DNA. Depending on their location, I concluded that the bloodstains may be the result of dripped blood from Zimmerman’s head as he leaned forward over Martin’s body while he was dead or alive, or transferred blood from his hands as he touched Martin’s shirt.

Note that if we assume the fingers and palms of Zimmerman’s hands were bloody with his own blood, we would expect to see his blood on Martin’s hooded sweatshirt, if he grabbed Martin’s two sweatshirts together with his left hand and pulled them down and slightly to his left as he fired the fatal shot.

Gorgogne did not find Zimmerman’s blood or DNA on the hooded sweatshirt. That probably means he did not have any blood on the underside of his left hand and fingers when he gripped the shirt and sweatshirt or, if he did, he did not transfer it to the sweatshirt.

It also may mean that he did not grip the sweatshirts, although I still believe he did.

Recall that Gorgogne did not detect any of Zimmerman’s blood on Martin’s sweatshirt. Witnesses Mary Cutcher and her friend Selma saw him straddling Martin’s back and leaning forward touching his back and neck with his hands after the shot. Therefore, I do not believe he had any blood on his hands.

No blood is visible on his hands in the photographs taken by police at the station house after the shooting.

That does not mean that blood was not on his hands earlier, however, because the police incredibly permitted Zimmerman to wash up in the washroom at the station house before the photographs were taken. That is inexcusable. It is what it is, however, and we cannot change it.

We do know that Gorgogne identified Zimmerman’s blood on the grip of his Kel Tec 9 semiautomatic handgun. Could that bloodstain have been already present before the incident that resulted in Martin’s death?

For example, DNA preserves indefinitely in a dried bloodstain, so Zimmerman might have deposited his blood via transfer to the grip sometime before the incident with Martin on February 26th. He might not have known it was there. I do not recall seeing any blood on the grip of his gun in the photographs that were recently released. Given PCR’s exquisite sensitivity, not much blood would have to have been present to yield a complete DNA profile.

Now let us take a look at Amy Siewert’s lab report. She is a firearms expert and her report was in the first document dump. She described the locations of the two holes in the sweatshirts and I compared what she wrote to Dr. Bao’s description in the autopsy report regarding the location of the entry wound.

Siewert said the holes in the sweatshirts aligned with each other and were 7 inches below the shoulder/neck seam.

Dr. Bao said the entry wound was 1 inch to the left of the midline and 1/2 inch below the nipple.

I am 1-inch taller and the same weight as Trayvon. I placed a mark on my chest corresponding to the location of the entry wound and then I took one of my white tee-shirts and placed a mark 7 inches below the shoulder/neck seam. I put on the tee-shirt and, using the marl on my chest, I marked the location of the entry wound on the tee-shirt.

I took off the tee-shirt and measured the distance between the two marks.

The two marks are a little over 3 and 1/2 inches apart. The mark representing the hole in the sweatshirts is above and slightly displaced toward the left shoulder.

To perform this comparison with precision, one would need to place the sweatshirts on Trayvon’s body and precisely measure the distance between the holes and the entry wound and determine the angle of their displacement from the vertical.

I could not do that, so I approximated the distance at 3 inches with a displacement toward the left shoulder.

Could my conclusion have been mistaken? I do not think so, but I have to admit that it is certainly possible. Fabrics stretch and there was only so much that I could do to reproduce the state of the State’s evidence.

I hope someone on the prosecution team followed up with Siewert and Dr. Bao to nail down this point as well as the apparent discrepancy between her characterization of the hole as having been caused by the muzzle of the gun in contact with the fabric and his characterization of the shot having been fired from an intermediate range (i.e., 0.5 centimeters to 1 meter).

I note for the record that Dr. Bao described the entry wound as 3/8 inch in diameter with a 2 X 2 area of stippling around the wound.

Stippling is caused by unburned gun powder that enbeds in the wound and its periphery. The farther away the muzzle of the gun, the larger the area of stippling. With handguns there is no stippling apparent when the muzzle of the gun exceeds 1 meter from the entry wound at the time the shot is fired..

Contact wounds characteristically cause the skin to tear. This condition is called starring and it’s caused by the expanding gasses released by the burning gunpowder.

Siewert observed torn fabric that spread out from the holes caused by the shot. She prepared some cutouts using fabric from the two sweatshirts (actually the interior one has been redesignated as a shirt by the DNA analyst) and test fired Zimmerman’s gun using the same ammo from several different distances, including a contact shot. The tearing in the result from the experimental contact shot matched the tearing in the hole in the sweatshirt and that is why she concluded that it was a contact shot.

Dr. Bao did not note any tearing or starring around the entry wound.

D. Vincent di Maio, a respected forensic pathologist and the former Medical Examiner for Bexar County, Texas (San Antonio) reviewed Dr. Bao’s autopsy Report and estimated the muzzle of the gun was 2 to 4 inches from the entry wound when Zimmerman fired the fatal shot.

Dr. Bao characterized the fatal shot as “Directly, front to back.”

That is all the evidence we have.

Consider these questions:

(1) Did Zimmerman grip Martin’s sweatshirt and shirt with his left hand?

(2) If he did not (or even if he did) how did he immobilize Martin so that he could aim and squeeze off the perfect shot to the heart, or was it just a lucky shot?

(3) How and when did Zimmerman sustain the injuries to his nose and the back of his head?

(4) Do you believe the injury to his nose was caused by the recoil of his gun when he fired the fatal shot?

(5) What do you believe explains the presence of Zimmerman’s blood on Martin’s shirt?

(6) What do you believe explains the presence of Zimmerman’s blood on the grip of his gun?

As I said, I hope the prosecution has figured out the significance of the evidence as it is important to the outcome of the case.

I still believe that the agonizing shriek that abruptly ended with the shot and the interrogation and begging that preceded it establish beyond a reasonable doubt that Zimmerman was not in imminent danger of being killed or suffering serious bodily injury when he shot and killed an unarmed Martin “evincing a depraved indifference to human life.”


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