Judge Ito presided over a day of intensive technical testimony on DNA mixture frequency statistics. The prosecution called Dr. Bruce Weir to testify about frequency calculations for mixed blood stains; the defense countered with Dr. William Shields to challenge Weir's methodology as assumption-laden and potentially misleading. After extensive 402 foundational hearings and evidentiary motions, Ito ruled to admit Weir's testimony with strict restrictions: clear disclosure of all assumptions, ranges calculated for two, three, and four contributors, and no reference to known genetic samples. Weir then testified to the jury on mixture frequencies from crime scene evidence.

• Judge Ito orders prosecution to present foundational showing on DNA mixture interpretation before Weir testifies
• Dr. Bruce Weir's direct examination establishes credentials and explains contributor-based frequency calculations for mixed blood statistics
• Heated cross-examination: Thompson challenges Weir's calculations as circular and built on assumptions tied to the prosecution's theory
• Defense calls Dr. William Shields to argue the simpler National Research Council method is more reliable
• Clarke systematically attacks Shields's credibility relative to Weir during tough cross-examination
• Judge Ito rules to admit Weir's mixture frequencies but requires clear labeling of assumptions and contributor ranges
• Dr. Weir testifies to jury on DNA mixture frequencies from Bundy crime scene and Rockingham glove