DNA And GSR Update On George Zimmerman Case

Summary of DNA and GSR Evidence*

A DNA Double-Helix

Image by Keith Ramsey

1. Trayvon Martin’s shirt (ME-8)

Four stains tested positive for blood. Trayvon Martin is the source of two stains. George Zimmerman is the source for another and the fourth stain is a mixed sample containing DNA from both individuals.

2. Trayvon Martin’s hoodie (ME 12)

Two stains test positive for blood. Trayvon is the source of one and no DNA result on the other.

No DNA results foreign to Trayvon Martin are found on both lower sleeves.

Two holes were discovered in the area of the “upper left chest” (one in each item of clothing) that exhibited characteristics consistent with a contact gunshot.

3. My thoughts

Given the lack of George Zimmerman’s DNA on the hoodie, the presence of blood contributed by George Zimmerman on the shirt that he was wearing underneath the hoodie indicates the hoodie was not covering the portion of the shirt where the bloodstain was located. Difficult to draw any additional conclusions without knowing the location of the bloodstains on the shirt (e.g., whether the hoodie was pulled up exposing the shirt or the shirt was extended below the hoodie or how this could have happened)

No DNA results foreign to Trayvon Martin are found on both lower sleeves suggesting that Trayvon was not beating Zimmerman.

The two holes obviously came from the same shot and there is a potential conflict between the location of the wound (1 inch left of the midline and 1/2 inch below the nipple) and the location of the two holes (upper chest area).

There also is a potential conflict created by the medical examiner’s conclusion that the muzzle of the gun was 2 to 4 inches away (an intermediate distance) when the fatal shot was fired compared the firearm’s analyst who concluded that the muzzle of the gun was in contact with the clothing.

Marilyn, who comments at my law blog, suggested Zimmerman was restraining Martin by gripping his clothing with one hand and fired the gun with the other as Martin was attempting to get away. This could explain how the upper part of both items of clothing could have been pulled down as well as a few inches away from Martin’s chest when Zimmerman fired the fatal shot. It also might explain how Zimmerman’s blood might have gotten on the shirt, but not the hoodie.

I think we lack sufficient evidence to draw that conclusion at this point, but it’s certainly possible. Might also explain how the shot went straight in without angling up or down, left or right.

Of course, if it happened this way, the shooting definitely was not in self-defense.

4. George Zimmerman’s shirt (DMS-16) and jacket (DMS-19).

Gunshot Residue (GSR) was found on the jacket in the form of 1 particle of lead found on the upper back portion of the right sleeve.

Twelve bloodstains on the shirt were contributed by George Zimmerman, according to DNA analysis.

Thirteen bloodstains on the jacket contain Zimmerman’s DNA. Trayvon Martin’s DNA is present in four of them (mixed samples) and his DNA was detected in one mixed sample where the other contributor could not be identifies.

5. My thoughts

We do not know the size of any of these bloodstains. but I imagine some are quite small because they probably were deposited by high velocity blood spatter from the gunshot, which resembles a fine spray.

The pattern of blood spatter may establish where the wound was in relation to the jacket when the fatal shot was fired and help to establish the relative positions of the two individuals.

The only conclusion one can draw regarding the presence of GSR is that the object in question was in a shooting environment at some time.

GSR can be wiped or washed off, and one cannot tell how long it has been present, so we probably cannot reliably draw any conclusions from the presence of the single particle of lead on the upper back portion of the right sleeve of his jacket.

*The information in this article comes from the lab reports in the document dump.

1. Lab Report March 26, 2012 (p. 104)

2. Supplementary Lab Report May 9, 2012 (p. 110)

3. Lab Report March 22, 2012 (p. 122)

4. Lab Report March 28, 2012 (p. 124)

25 Responses to DNA And GSR Update On George Zimmerman Case

  1. Tasha Harris says:

    I believe the bruise and blood on Zimmerman’s face along with his own blood spatter came from him hitting himself in the face with the gun after his close range shot with one hand. What we know for sure is that he was not smothered while that blood was on his face as it is pristine, fresh, and not smeared. Its also telling that his blood and TM’S spatter could be mixed, it obviously happened simultaneously.

  2. We know the shooting was not in self defense. Trayvon was not committing a crime when he was shot. Against Zimmerman or anyone else. It’s just a bunch of bogus bull.

  3. Tavia says:

    Also please don’t forget that Zimmerman spoke to Joe Oliver and Oliver has suggested that “we are not sure that George is the one who shot Trayvon.” With the DNA not being George’s on the trigger it makes me wonder did someone else kill Trayvon or was it other people at the crime scene. I really think that by Joe Oliver speaking to George that George has told him something different than what he told the police. I could be wrong but I have a funny feeling something is fishy going on with this case.

  4. ajamazin says:

    I read as much as I can on the Trayvon Martin case.

    I have seen conflicting reports/opinions as to the positions of Trayvon and Zimmerman at that time Zimmerman killed Trayvon.

    Were one or both standing at the time the shot was fired?

    How on earth did Zimmerman manage to be found straddling a dead or dying Trayvon who was face down in the grass?

  5. thejbmission says:

    What about the tapping sound you hear in the 911 call? Some people seem to believe it sounds like a knock on a door?
    Don’t tell me Zim killed this kid earlier or elsewhere? And then found someone to help him make it look like it just happened?
    Now that would be brilliant, so probably not. lol

    It’s hard for me to imagine that if TM was on top, how does Zim manage to pull a gun without TM wrestling with it? I would think his fingerprints would be on the barrel of the gun. I’d also expect to see wrist burns or scratches on the Zim’s wrists.

    • No prints were found on the gun, which is not unusual, by the way.

      There were no scratches, cuts or bruises on Zimmerman’s hands.

      There was one abrasion on the top of Trayvon’s ring finger, 3/8 to 1/4 inch long above the knuckle in the location where a ring would normally be.

      Don’t know what caused the knocking sound, but I think it’s a stretch to suggest an accomplice.

  6. Nicole says:

    Maybe Just Maybe the unknown Blood stains come from the neighbor that has been campaigning for Zimmerman.Maybe when he helped Zimmerman contain injuries he got hurt.

    • Hard to say, but no matter how he got them, they are not serious injuries and he was not justified in using deadly force because he was not in imminent danger of suffering death or grievous bodily injury.

      Trayvon Martin, on the other hand, was in such danger and certainly justified in using the less than deadly force to defend himself against Zimmerman.

      That’s the proper legal framework to use in analyzing this case.

      • Letty says:

        If you listen closely to his call to police he sounds distracted while talking to them and it sounds as if he is knocking on somoenes door.

        • I don’t know if he smokes, but it sounded to me like he was trying to light a cigarette letter.

          Oh well, I don’t know what caused that sound or if it’s an artifact on the tape, like static.

          Or maybe he’s tapping his fingers on the phone.

          Who knows?

          Are you suggesting that a third person is involved?


          What did he do?

          I’m not saying it didn’t happen. I just don’t see how it fits into this case.

          I agree that he seemed distracted, but I think he wanted to end the conversation and go find Trayvon because he thought he was going to get away.

      • James (googledad) Johnson says:

        The proper framework to use in analyzing this case is subjective as to a desired outcome. We can ignore the lack of evidence, because at cvertain points we can believe Mr. Zimmerman, but on other points, he is obviously lying. Whatever it takes to prove that he killed a young black man is what we need.

        • I cannot agree with your statement because I have seen and read about many prosecutors who have concealed material exculpatory evidence from the defense and, in some cases, even suborned perjury to get a conviction.

          We do not need to make stuff up because the evidence in this case is overwhelming. George Zimmerman did not kill Trayvon Martin in self-defense and he has lied repeatedly while claiming that he did.

  7. ajamazin says:

    O’Mara has stated that he may move to suppress Zimmerman’s confession.

    “DNA forensics of the gun used that night show that Zimmerman’s DNA is on the firearm, except for the trigger.

    According to the report, another individual’s DNA was on the gun, but experts could not identify whose it is.”

    Corey has submitted it for further analysis.”

    O’Mara might wish to make it a relevant issue.

    • Regarding the admissibility of his “confession:” It’s really and exculpatory statement, assuming it’s true. It turns into a “confession,” if it is false.

      Since O’Mara is thinking about filing a motion to suppress it, he must be thinking the State can disprove it and use it as a sword. I’m not surprised he sees it that way. I do too and I know less than he does.

      First issue is whether Zimmerman was in custody and being questioned. If so, he has to be Mirandized and agree to waive his right to remain silent. If that happened, his statement is admissible under Miranda v. Arizona. If not, his statement is not admissible during the prosecution’s presentation of its case, but it is admissible during the defense case, if he testifies and tells a different story.

      Second issue is whether his statement was voluntary, as opposed to coerced or obtained by threat, physical intimidation, or torture. I doubt his statement was involuntary since he volunteered it before he was even arrested by saying, “I shot him in self-defense.”

      That means the success of the motion depends on whether there was a Miranda violation.

      Again, Zimmerman told a civilian at the scene before the cops arrived that he killed Martin, but he claimed he did it in self-defense. That statement is admissible because he made it to a civilian and the Miranda rule does not apply to statements made to civilians. So, even if he persuaded the judge to exclude the statements to police under Miranda, the statement to the civilian would still come in.

      Having admitted that he pulled the trigger, I don’t know why someone other person’s DNA on the gun matters, unless he has some wild theory that someone else killed Trayvon. But two witnesses saw him with Trayvon and Trayvon didn’t shoot himself.

  8. ajamazin says:

    I have read the following:

    “There is yet to be identified DNA on the trigger of his gun.
    It does not belong to Zimmerman or Trayvon.

    Trayvon’s DNA was not on any portion of the gun or the holster.
    Zimmerman’s DNA was not on the trigger of the gun.

    A third piece of DNA , still to be identified, was found on the trigger.

    Corey is awaiting further DNA analysis to come back.”

    What does this mean?

    Who “pulled” the trigger?

    • Only two people were seen wrestling. Zimmerman said he pulled the trigger and Trayvon has been eliminated.

      That leaves only two possibilities.

      1. The stain tested positive for blood, but is not human blood.

      2. The stain is human blood, but not from Zimmerman or Martin.

      In both cases, the blood likely was transferred from the hand of someone who came in contact with the trigger and transferred human (probably their own) blood or animal blood, which was on their fingers, by squeezing the trigger.

      We don’t know how long the blood was on the trigger and I don’t know when he acquired it. Could be a previous owner or user. Hard to say.

      Wonder when it was last used and by whom?

      Could also be a false positive test result for blood. I don’t think the lab routinely does confirmatory tests after getting a positive result for the presence of blood before proceeding with a DNA test (not sure).

      Also, if the original sample is degraded, might not have been possible to get an interpretable result.

      Bottom line: Zimmerman said he shot him and I see no reason not to believe him. Therefore, this probably is an irrelevant issue.

  9. The presence of Zimmerman’s blood on Martin’s shirt under the hoodie also suggests that, at some point, Zimmerman was above him, assuming the stains are due to dripped blood.

    Another possible explanation is transfer. That is, the blood was on Zimmerman’s clothes and transferred to Martin’s shirt when they came in contact.

    Dripped blood looks like a circle, unless the surface it impacts is angled, in which the blood spatter appears elongated. Absorbent cloth can affect the appearance. Transferred blood typically looks smeared.

    A qualified blood spatter expert can interpret patterns of spatter and interpret how a murder was committed and I have no doubt that the prosecution will employ a blood spatter expert, unless they already have one working for the Florida State Crime Lab.

    I know a fair amount about the subject because it has come up in several of my cases.

    Problem is I have to see the stains to figure out what happened and the only thing I have seen are the reports I’ve mentioned here.

  10. Thanks, Marilyn, for your tip about the blog discussion and your theory.

  11. I forgot to add the DNA analysis about Trayvon Martin’s fingernail scrapings.

    Right hand (ME-2A): tested positive for blood containing Trayvon Martin’s DNA.

    Left hand (ME-2B): no result.

    By the way, the numbering system, which in this instance is ME-2 A&B, means the medical examiner’s office obtained the fingernail clippings in two envelopes labeled A & B at the autopsy and submitted them into evidence in one larger envelope as Exhibit ME-2.

    Other exhibits are typically numbered with the officer’s initials who placed them into evidence.

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