Making A Murderer...Or an Effective EDTA Detection Test

On a cold December day in 2015, many Netflix subscribers cuddled up with their hot chocolate and blankets and watched a documentary series which would eventually become a national outcry. This series is called "Making A Murderer", and it follows the story of Steven Avery - a man whose innocence is questioned based on many different factors. One of these factors is the result of a blood EDTA test, and that's what  Dave Mosher, of Business Insider, wanted to shed some light on in his article.

For those who haven't watched the show: please do. I'll try to not give away any spoilers, but in short, Steven Avery was accused of murdering Teresa Halbach, and one of the major incriminating evidences was that her car was found on Avery's property. Beyond that, a dried blood sample was taken from the car and found to be Steven Avery's through DNA testing. Seems like a closed case, right? Well, this is where the conspiracy starts. Steven Avery had been convicted before for a sexual assault crime that he would later be deemed innocent for after DNA tests. However, they had collected a blood sample from him in 2002. The documentary explores the idea that the blood was planted by the police, which doesn't seem too far-fetched as you watch the series. However, how could someone prove that the blood was planted or naturally? It boils down to concentrations of ethylenediaminetetraacetic acid, or EDTA, in the blood samples found. 

Chemical Structure of EDTA, Wikipedia

This compound is used in blood samples as a preservative, and will keep the blood from coagulating, as in it keeps the blood liquid. EDTA is not naturally found in the blood, because if it were, when you got a cut you would keep bleeding and die. So seems simple right? Collect the blood sample from the car and test it for EDTA. However, at the time, there was no standard for EDTA testing, and the FBI used a new method to determine that there was no EDTA in the blood, therefore concluding that Avery was at the crime scene. Also, the FBI tested 3 of the 6 blood stains, yet drew the conclusion, "within a reasonable degree of scientific certainty", that all of the blood in Halbach's car was EDTA free, and therefore linking Avery directly to the crime. Many people are concerned with the accuracy of the new method of determining the EDTA detection, as well as only testing half of the blood samples.

Trial Exhibit 435 - FBI EDTA Test, the conclusions that helped incriminate Avery, Business Insider

This case, along with many others, relies on scientific evidence to determine innocence and guilt. However, in this unusual case, the science is highly questioned. I believe this is a call to action to make sure that all scientists work professionally and not for the benefit of any side other than the truth. Also, it calls for a standardized test to determine EDTA accurately to help further forensic science and help in the criminal justice system, instead of creating confusion and controversy.