DNA Analysis Links Two Pennsylvania Cold-Case Murders to Suspect After Nearly 50 Years

Forensic DNA analysis has helped Pennsylvania investigators connect two murders committed nearly 50 years ago and identify a deceased man as the alleged perpetrator. The cases, involving Susan Rush and Brenda Ritter, were revisited using specialized DNA interpretation software developed by Cybergenetics.

Pennsylvania State Police announced on November 4, 2026, that James Richard Clark Sr. had been identified as the suspect in both killings. Additional details about the forensic analysis were reported on November 9.

Rush, 21, disappeared in November 1976 after leaving a shopping mall in Washington County, Pennsylvania. Her body was discovered the following morning in the trunk of her vehicle. Investigators determined that she had been sexually assaulted and strangled.

Approximately six months later, 18-year-old Ritter was found dead in the same county. Investigators identified similar circumstances, including sexual assault and strangulation.

Despite extensive investigations, neither case resulted in an arrest.

In May 2025, Pennsylvania State Police submitted previously developed DNA data from both investigations to Cybergenetics for additional analysis.

The evidence included biological material recovered from clothing associated with Rush and from samples collected during Ritter's investigation.

Different laboratories had previously generated autosomal short tandem repeat (STR) data using different testing kits.

Cybergenetics applied its TrueAllele probabilistic genotyping software to interpret the DNA evidence and compare genetic profiles associated with the unknown male contributor.

Probabilistic genotyping uses statistical models to evaluate DNA profiles, particularly when samples contain mixtures of genetic material from multiple individuals.

According to Cybergenetics, the comparison produced a reported match strength of approximately one million, providing strong statistical support for the proposition that the two evidence samples contained DNA from the same unknown individual.

This finding connected the previously separate homicide investigations.

Subsequent work involving public and private forensic specialists led investigators to identify Clark as the suspect.

Authorities said Clark lived in the Washington County area during the 1970s. He was approximately 19 years old when Rush was killed and 20 when Ritter died.

Clark died in 2023 at the age of 66 and therefore cannot face criminal prosecution.

The case demonstrates how preserved biological evidence can remain valuable decades after its original collection.

It also highlights the distinction between establishing a DNA association and determining criminal responsibility. A statistical DNA comparison supports conclusions about genetic profiles but does not independently reconstruct every circumstance of a crime.

The reported match strength relates to the comparison between the two evidence profiles; it should not be interpreted as a direct probability that Clark committed the murders.

Investigators have not publicly disclosed every analytical step used to establish Clark's identity.

Pennsylvania State Police are continuing to examine whether he may be connected to other unsolved cases, but no additional victims have been confirmed.

The investigation illustrates how advances in DNA interpretation, combined with long-term evidence preservation, can provide new investigative leads in cases that remained unresolved for generations.