Defense attorney Peter Neufeld systematically dismantled LAPD SID criminalist Andrea Mazzola's credibility through a full day of methodical cross-examination, exposing inadequate training, protocol violations, and contradictory testimony about evidence collection. Most damaging was the prosecution's own demonstration video, which revealed repeated contamination: Mazzola resting her hand on concrete, dropping swatches, and failing to change gloves between samples. The day exposed systematic deficiencies in LAPD evidence handling procedures and raised serious questions about the integrity of the blood evidence central to the prosecution's case.

• Mazzola admitted she was a probationer with only 2 prior crime scenes yet served as the primary blood stain collector in the Simpson case
• LAPD provided no written manuals, protocol guides, or training on evidence tampering prevention to SID personnel
• Mazzola gave three contradictory versions of who collected blood drops at Rockingham with no notes or documents to explain the shifts
• Post-testimony meeting between Mazzola and supervisor Fung to reconstruct evidence collection, followed by new entries in field notes
• Prosecution's demonstration video showed Mazzola repeatedly resting her hand on dirty concrete, dropping swatches, and failing to change gloves between samples
• Prosecution still-photo board omitted dropped swatches and other contamination evidence visible on the videotape
• Mazzola failed to photograph or phenolphthalein-test key areas of the Bronco interior despite being trained to document all potential blood evidence