DELPHI TRIAL DAY 7: "Magic Bullet" & Gun Analysis

The expert witness Melissa Oberg testified that an unspent cartridge found at the crime scene (Item 16) was ejected from a firearm seized at Richard Allen’s home, specifically linking it to a Sig Sauer P226 model (Item 314) through tool mark analysis. This conclusion, supported by microscopic comparisons and a second examiner’s verification, forms the core of the prosecution’s case.

Key Takeaways:
• Melissa Oberg, a 17-year veteran forensic scientist with over 112 trials and 6,500 examinations, testified that Item 16—an unspent cartridge found between Abby and Libby’s bodies—was ejected from a Sig Sauer P226 (Item 314) found at Richard Allen’s home 27:01.
• She explained that tool marks form when a harder object presses against a softer one, with ejection marks appearing on unspent cartridges when they are expelled from a gun’s chamber, not just removed from the magazine 28:18.
• Oberg’s analysis involved comparing Item 16 with multiple firearms, including those seized from water-damaged or unidentified sources, and concluded none matched, reinforcing the link to Item 314 30:00.
• The prosecution played a factory video showing Sig Sauer’s manufacturing process to illustrate how individual tool marks can form even in mass-produced guns, supporting the idea of unique characteristics 35:07.
• During cross-examination, Oberg acknowledged that while she has never made a mistake in her career, she cannot exclude all possible firearms from matching Item 16, and noted criticism from PCAST and the National Academy of Sciences regarding insufficient research in the field 48:10.

The prosecution’s case hinges on the forensic link between the unspent cartridge and Ri