Cybergenetics Corp. assisted the Washington County (Pennsylvania) Police in their DNA identification of serial killer James Richard Clark Sr., who raped and murdered two young women 50 years ago.
Rush was 21 years old when she disappeared on Nov. 24, 1976, after leaving a local shopping mall. She had planned to meet her family at church but never arrived. The following morning, Thanksgiving Day, her brother located her vehicle along North Avenue in the City of Washington. Rush was found deceased in the trunk. Investigators determined that she had been sexually assaulted and strangled.
Six months later, Brenda Ritter’s nude body was discovered in a field two miles away—she too had been raped and strangled.
In May 2025, the Pennsylvania State Police (PSP) sent Cybergenetics DNA data, asking if the two cases shared DNA from an unknown person.
The Susan Rush swab included a sperm fraction from green pants. The Brenda Ritter swab showed spermatozoa from pubic hair. Different DNA labs had developed conventional autosomal DNA data from these evidence items using different STR kits.
From the case data, TrueAllele software isolated the unknown male genotypes. TrueAllele then compared the two evidence genotypes, finding a match strength of a million. This new cold case DNA lead linked the two cases to the same unknown man—the serial killer.
Cybergenetics testing established that the same offender murdered both Susan Rush and Brenda Ritter. TrueAllele analysis confirmed there was a serial killer in Washington County during the 1976 to 1977 timeframe.
Later work by public and private DNA investigators identified this unknown serial killer as James Richard Clark Sr., now deceased. This week the police announced that Clark committed the sexual assaults and homicides of both Susan Rush and Brenda Ritter.
Data from Cybergenetics