EDTA and Making a Murderer

In January 2016 I and many millions of others found themselves hooked on a Netflix TV series called Making a Murderer.  At the end, I was left with a big question: did Steven Avery commit the crime?

The morning after having watched the last episode, I had a brainstorm that I thought would be a great way to help solve the crime: crowdfund a prize to advance forensic science to improve the test (for "EDTA") that the show implied might exonorate Avery.  But after reaching out to experts in the forensic science field, my simple crusade got much more complicated.

Here's a sample of what I and my friends came up with:

- An excerpt from the proposed crowdfunding page

- An excerpt from the proposed crowdfunding page


On 18 March 2007, Manitowoc County, Wisconsin resident Steven Avery was found guilty of murdering photographer Teresa Halbach.  Halbach had gone missing on 31 October 2005.  On 18 December 2015 Netflix released Making a Murderer, which recounts Avery’s story and strongly implies the possibility that he is innocent.

In his 2007 trial, Avery’s lawyers argued that some of the evidence against him might have been planted to enhance the state’s case against him.  In particular, there was a blood stain in Halbach’s Toyota RAV4 that may have been planted using a sample of Avery’s blood the sheriff’s office had in their possession.

Photo from  Making a Murderer , obtained via Reddit

Photo from Making a Murderer, obtained via Reddit

To preserve a blood sample, the chemical compound Ethylenediaminetetraacetic acid (EDTA) is added.  This compound does not occur in the human body, so a test confirming its presence on the RAV4 Avery blood stain would provide strong “smoking gun” evidence of police evidence tampering.

Unfortunately, as shown in episode 6 of Making a Murderer, no such EDTA test exists.  The FBA was asked to test the sample for EDTA but the detection threshold of their test was arguably too high to make a determination.

Accordingly, I had an idea, in the tradition of the XPRIZE competitions, to organize an inducement prize contest, to encourage the development of a sufficiently accurate EDTA test to re-test the RAV4 blood stain.

What an EDTA test would accomplish

If Avery is innocent: Just as advances in DNA testing technology exonerated Avery of his 1985 wrongful conviction, if he is also innocent of the Halbach murder, advances in EDTA testing technology could exonerate him here.

If Avery is guilty: On the other hand, if he did in fact commit the crime, a high-resolution EDTA test would help to quell doubts about his guilt held by many, since Avery’s version of events would be categorically refuted by the presence of his blood in Halbach’s RAV4.

As an additional benefit, the EDTA test would be added to the forensic arsenal, and could be helpful in many more cases than simply the Avery case.

I and some friends came up with some award criteria:

  • $50,000 USD (or higher if more funding is obtained), obtained through crowdfunding.

  • The prize money will be held in a US dollar account which has been placed into a Canadian Specified Trust.  The trustee is a Canadian lawyer who is obligated by law to disburse the funds net of fees to the first individual or entity to satisfy the contest criteria.

  • The trustee is not affiliated with the Avery or Halbach families, current or former Avery defense attorneys, nor with any Wisconsin district attorney offices.

  • If the trustee determines that a scientist or lab has met the criteria outlined below, the money will be disbursed net of payment processing and crowdfunding fees.

  • If no scientist or lab has met the criteria by the time Steven Avery dies or if he is fully exonerated by other means, the trustee will dissolve the trust and transfer all prize money to the Innocence Project.

  • The award money raised by crowdfunding is paid into a Trust established with a Trust Deed specifying that all funds are to be disbursed directly to the contest winner as determined by the criteria outlined above.

  • It is not possible for the organizers of this crowdfunding to access the funds raised at any time.  Your donation is legally assured to go to the specified cause.


At this point I had a crowdfunding pitch drafted and a team of friends ready to help get the word out.  There was just one problem: I didn't know how to phrase the problem statement in a way that made scientific sense.  Not being a forensic scientist, I reached out to a few people, asking them for help.

I was impressed by the accessibility and candor of these forensic academicians.  Here is a response I received from two of the most senior figures in American forensic science:

The committee that was asked to review your request to publicize the EDTA testing challenge has decided that we should decline your request. I will admit that I do not fully understand why you believe that current testing should be improved. Nonetheless, the committee believes that such testing is currently readily available and did not want to involve the Academy in this effort. I wish you well.
— Dr. Victor Weedn, President of the American Academy of Forensic Sciences
I do not wish to ‘formulate the statement’ but I will offer what is usually required for such a ’test’. We call it the five S’s. The five S’s include:

- Sensitivity
- Selectivity
- Specificity
- Simplicity
- $$$$$$$

Thus to be certain of scientifically valid results the method/technique/procedure must have defined and demonstrated detection limits for the analyte/sample in question (e.g. High sensitivity in the sample matrix), be highly selective and specific (e.g. There is no other chemical finding possible), be simple to execute so that all errors are eliminated, and be sufficiently inexpensive that participating laboratories can afford the best techniques and instrumentation available. In addition, an active applied research program should exist such that new technology and methods can be employed for solving the challenging cases which appear in the future.

None of these are trivial to accomplish but all are certainly possible.

As I say above I do not wish to formulate a statement, but above would be what I encourage you to consider in such a statement.
— Chief Science Officer of a Bioanalytical Services Company

Here's another exchange I had, with an expert in the field of forensic EDTA testing:

Dear Dr. McCord,

I was given your name by Dr. Robin Sheppard. She suggested you might be willing to comment on a prize in forensic chemistry that we are crowdfunding.

Your 1997 article discusses testing EDTA, which is relevant to our contest criteria:

Miller, ML; McCord, B.R.; Martz, R.; Budowle, B. The analysis of EDTA in dried bloodstains by electrospray LC-MS-MS and ion chromatography. Journal of Analytical Toxicology, 1997.

Would I be able to speak with you by telephone for 5 minutes on Wednesday or Thursday of this week? If so, please let me know of a time and I’ll be happy to call.
— Michael Currie
Dear Michael,

Since I have already developed such a test, why not just send me the money?

It would be quicker.
— Dr. Bruce McCord
Dr. McCord,

I appreciate your response - it may be that I’m phrasing my question incorrectly then. :)

I hope you will agree that the tens or hundreds of thousands of dollars raised for this award should be going to good science. If you’d be willing to take a 5-minute phone call to discuss in a more informal capacity how best to spend this money to improve forensic science, I’d greatly appreciate it.
— Michael Currie

The problem seems to me that you are letting the wrong people define the issue and the science is getting lost.

If you look at a tube of blood with EDTA in it the concentration of EDTA in the blood is 1.8mg/mL

You are asking for a test to detect 0.0002 mg of EDTA in a 1 mL sample.

Why? That is about 10,000 times lower than what would be in the blood from a tube

When Edta is in blood it is not hard to find. At all…
— Dr. Bruce McCord
Dr. McCord,

You say EDTA is present in a concentration of 1.8 mg/mL in a prepared tube of blood. If the blood from that tube was swabbed onto a surface and left to dry, would much of the EDTA evaporate, necessitating a higher threshold? That’s what Dr. Chad Steele alleges in his blog.

In the Making a Murderer documentary a blood stain was alleged to have been planted by police. The stain was dried on a car interior. The FBI issued the following report, but the defense lawyers argued the FBI protocol was not scientifically valid and anyway did not have a sufficient detection threshold to definitively exclude the possibility of EDTA being present on the blood stain.

If your opinion is that the original FBI report was conclusive and definitive and proves the blood stain came from fresh blood, then the whole premise of my team’s crowdfunding idea has been upended, and there is no need for a prize at all. Please confirm. :)

Thanks again for your time.
— Michael Currie
EDTA is a very interesting molecule. It is a chelator, which means it binds strongly to metals. It is often in the salt form. Both of these things mean that it is not particularly volatile. (so wont evaporate at any appreciable rate)

Liquid forms are said to be stable for a year and if dried, it is likely to be stable even longer.

Lawyers are not chemists, and if you look at any of the articles on EDTA detection in blood (there are several) you will see that all of them mention a detection limit. What is Dr. Steele talking about?

The basic problem is that the presence of DNA is deadly to a defendants case. The only defense is to state the blood is planted.

I think that if you want to help forensic science go after the problem of sample backlogs for violent crime. There is not sufficient funding for lab work.
— Dr. Bruce McCord

It was at this point that it became apparent that the EDTA test used was perfectly adequate - the issue was with the FBI's experimental protocols.  Even so, it seems the defense case in this area was far less convincing that the show made it out to be.  I decided that the state of the art in EDTA testing did not need to be advanced, and was already perfectly adequate.

Thanks to all of the academics and lawyers who spoke with me and gave me their valuable time.  Thanks as well to the friends who engaged in many great conversations with me about this - it was quite stimulating!