Dr. Fredric Rieders, a Vienna-born forensic toxicologist and laboratory director, testified as a defense witness in July and August 1995. He testified that EDTA, an anticoagulant preservative used in blood-collection tubes, was detected in evidence from Nicole Brown Simpson's back gate and the defendant's sock at levels approximately 1,000 times higher than dietary sources could produce; he presented those findings as supporting the defense theory that blood from preserved samples had been planted. Marcia Clark cross-examined him over proceedings on July 24 and August 14, after which Robert Blasier conducted redirect examination; Rieders also testified as a defense witness in the civil trial in December 1996.