Overview

• Systems engineer Nathaniel Adams testified that Astrea Forensics’ IBDGem software failed 21 nationally accepted verification standards and underwent multiple updates after testing hairs in this case.
• District Attorney Ray Tierney challenged Adams’s expertise by questioning his educational credentials and noting his history of defense-only testimony.
• Prosecutors maintain that probabilistic genotyping is widely accepted and say rootless hairs from six victims link Rex Heuermann to killings between 1993 and 2010.
• Heuermann’s defense has asked the court to split the seven murder counts into five separate trials to mitigate potential jury prejudice.
• Judge Timothy Mazzei is expected to rule soon on the admissibility of the contested DNA evidence and on whether the charges will be tried together or separately.