Simpson Jury Hears Experts Argue Whether Bloodstains Are Authentic
Is it there or isn’t it there?
For two days, the jury in the O.J. Simpson trial has listened to starkly conflicting testimony about a preservative called EDTA and whether it is present in bloodstains found on a sock in Simpson’s bedroom and on a rear gate at his ex-wife’s condominium.
On Monday, defense expert Fredric Rieders said he reviewed FBI tests and concluded that it was present. Tuesday, the FBI expert who conducted the tests, Roger Martz, said just the opposite.
At issue is the credibility of key evidence in the state’s case. DNA tests show that a stain on the sock matches his ex-wife’s blood, and that blood on the gate - collected three weeks after the June 12 murders - matches Simpson’s blood.
Simpson’s lawyers say the blood was planted, taken from vials of preserved blood that police took from Simpson and from Nicole Simpson’s body.
Martz said Tuesday he found traces of EDTA, but that the levels were too low to warrant identification. “These stains did not come from preserved blood,” Martz said.
He also said he tested his own blood and found EDTA present at virtually the same levels as were present on evidence stains.
But on questioning by the defense, Martz conceded he had never tested for EDTA before, that a test he did showing EDTA in his own blood was not reliable.
Martz tested his own blood to show that EDTA, which is a common food preservative, is present in most people’s blood. That finding was ridiculed by Rieders as absurd; Rieders said anyone with that level of an anticoagulant, such as EDTA, would be bleeding all the time.
Tuesday, Martz acknowledged that his blood was drawn into a test tube and that he neglected to determine whether EDTA or any other preservative was already in the test tube.