Day 122 focused on competing examinations of FBI chemist Roger Martz's EDTA testing of blood from the sock and rear gate. Clark emphasized the distinction between detecting and identifying a compound and elicited testimony that EDTA was not positively identified in the evidence stains. Blasier challenged Martz's methodology through destroyed raw data, undocumented procedures, sample-quantity estimates, stability assumptions, and ion-count comparisons. On recross, Clark elicited testimony that oversampling favored detection of any EDTA signal and challenged a defense chart, while Blasier continued disputing detection limits before Martz defended his experience.

• Defense granted motion to treat FBI Agent Martz as hostile witness
• Clark established critical distinction between 'detecting' versus 'identifying' EDTA compounds
• Blasier exposed that Martz destroyed raw mass spectrometry data for key evidence samples
• Martz admitted conducting an 'informal dilution experiment' 'for dramatic effect' with no documentation
• Martz could not recall the value of pi, prompting judicial intervention and damaging his credibility as forensic expert
• Defense used Martz's metal-to-metal ion-count data to argue for an approximately 14-fold difference rather than the thousand-fold difference the prosecution's charts implied
• Multiple sidebars erupted over exhibit admissibility and chart methodology
• Martz conceded he never attempted larger blood quantity tests despite suspecting EDTA might be present