Back to Newsroom
SDDA Cynthia Zimmer explains DNA evidence in serial rape case
Kern County Supervising Deputy District Attorney Cynthia Zimmer spoke at last month’s full day Justice Through Science™ forensic conference in Pittsburgh. Her hour-long talk was on the highly watched People of California v. Billy Ray Johnson case and its DNA mixture evidence.
The Eastside Rapist was attacking minority women in Bakersfield, CA and molesting their daughters. Identified through DNA on a zip tie, TrueAllele® computing separated DNA mixtures on eight evidence items to provide physical evidence implicating Johnson. Independent TrueAllele analysis by the crime lab and Cybergenetics agreed. A defense expert conceded that Johnson left his DNA.
Johnson was convicted, and sentenced to life plus 432 years. Defense advocate lawyers have written about Johnson’s appeal in the New York Times, Wired and elsewhere, demanding access to the TrueAllele source code that Cybergenetics already provides.
SDDA Zimmer's YouTube talk was followed by talks from a public defender, an innocence lawyer, and a TrueAllele exoneree.