 During direct examination he initially testified the blood samples "responded like EDTA responded" and "was consistent with the presence of EDTA" but then stated that he could not identify EDTA in the evidence samples This apparent turnaround during direct examination stunned the defense and when they accused Martz of changing his demeanor during the lunch break he admitted he had because he realized he was not being entirely truthful in his testimony before because he was only giving "yes" and "no" answers.During cross examination, Martz narrated his answers and stated EDTA is also used in food and detergents and not just blood test tubes.Martz demonstrated this by testing some of Nicole Brown's clothing that did not have blood on it and found EDTA was present.