Netflix

The test was based on finding a chemical called EDTA. It is found in the evidence vials that store blood. If it was found in Avery's blood samples taken from victim Teresea Halbach's car, then it would have suggested someone took his blood (which was in the possession of the police) and planted it on the scene of the crime. The test, which was conducted by the FBI at the request of the state with little documentation, didn't detect it.