For decades, two families in Washington County, Pennsylvania, mourned their daughters while the answer to who killed them remained a mystery. Now, nearly 50 years after the pair of murders, authorities say a serial killer was responsible. Susan Rush, a 21-year-old clerk, was last seen leaving the shopping center where she worked one night in 1976. She was headed to church to meet her family for a Thanksgiving Eve dinner, but she never arrived. Her brother found her in the trunk of her car the next morning. She had been sexually assaulted and died of asphyxiation due to strangulation, police said. Six months later, 18-year-old Brenda Ritter was murdered after leaving her boyfriend’s house on a stormy night in May 1977. Her body was found on a hill the following day. She, too, had been sexually assaulted and strangled, police said. Despite efforts by local and state investigators, their families went years without an answer to who killed them. But now, evidence preserved from both crime scenes has led investigators to determine a serial killer was responsible for their deaths. Pennsylvania State Police identified now-deceased James Richard Clark as the killer at a news conference Wednesday. “Testing identified that the same offender murdered both Susan Rush and Brenda Ritter. This testing confirmed there was a serial killer in Washington County during this time frame,” said Cpl. James Petrosky of the agency’s Criminal Investigation Assessment Unit. These killings are the latest in a growing number of cold cases solved thanks to advancements in DNA technology. Earlier this year, DNA extracted from chewing gum led authorities in Washington to the man responsible for two murders in the 1980s, while a DNA sample from an ancestry test helped investigators identify the remains of a Second World War veteran who went missing in 1965. Two homicide investigations go cold After Rush failed to show up at the church, her family reported her missing. The next morning, while searching the city for her, Rush’s brother found her abandoned car along a road. The car was locked, and her body was in the trunk, Petrosky said. She had a fractured larynx and had been strangled, The Pittsburgh Press reported two days after her killing. Rush’s body had been hastily clad, the Pittsburgh Post Gazette reported — she was wearing only a pair of green slacks and a turtleneck sweater, which was inside out. Her bra and underwear were on a seat inside the car, then-Washington County Coroner Farrell Jackson told the newspaper. An autopsy later determined she had been sexually assaulted and strangled, Petrosky said. The Pittsburgh Press talked to Ritter’s brother Terry shortly after the killing, who said Ritter had received her beautician’s license just three weeks prior and had hoped to find a new job in that field. Investigators developed many leads and persons of interest following her death, but none led them to her killer, Petrosky said. About six months later, Ritter, a recent graduate and secretary of a construction company, was also killed. On the morning of May 19, 1977, Ritter’s mother called her boyfriend’s house to speak with her. She reported her daughter missing after learning she had left her boyfriend’s house the night before, during a thunderstorm, and never made it back home. Her boyfriend and his mother had ensured Ritter locked her car doors before she left, Petrosky said. Later that day, Ritter’s car was found abandoned along a rural road near Washington. A search with a police helicopter located her body on a hill about three-quarters of a mile from her car, according to Petrosky. Her clothes were found 50 feet from her body. She, too, had been sexually assaulted and strangled, authorities said. Ritter was wearing only brown shoes and blue socks when she was found, the Pittsburgh Press reported. Following Ritter’s murder, authorities looked into whether the two deaths were connected. Don Zofchak, then-police chief in South Strabane Township — where Ritter’s body was found — told the Pittsburgh Post Gazette there were similarities between the two cases. However, like with Rush, numerous leads in Ritter’s killing led nowhere, Petrosky said, and both cases went cold. It would take authorities nearly five decades to officially connect the two killings. A break in the cases In 2008, DNA from Ritter’s investigation was uploaded to CODIS, the FBI’s DNA profile database. An unidentified male DNA profile was created, Petrosky said. Though the database was checked weekly, investigators found no matches to any offender profiles. In 2025, investigators submitted DNA evidence from both cases to multiple biotech companies that work with law enforcement on cold cases, including Cybergenetics Corp, Othram, PTC Laboratories and Identifinders International, for further analysis. Authorities hoped their laboratory testing could determine whether the samples contained DNA from the same person and eventually point them to a suspect. Cybergenetics isolated the unknown person’s genotypes from each DNA sample and compared them to determine whether the cases were connected. The analysis revealed an extremely high likelihood of a match between the two profiles, the company said a news release. The findings officially linked the two murders, confirming there was a serial killer active in Washington County at the time, Petrosky said. The DNA evidence allowed investigators to develop a potential suspect profile, which ultimately led to Clark, according to Petrosky. Authorities did not provide further details about how they connected their DNA profile to Clark, though the companies involved often use investigative genetic genealogy, in which a DNA profile is compared to those available on different genealogical platforms to find a relative and then to build out the family tree to find the suspect. Clark was living in the Washington area at the time of the murders, according to Petrosky. He would have been 19 years old at the time of Rush’s death and 20 years old at the time of Ritter’s. Authorities declined to say whether he had a known criminal history, citing the ongoing investigation. Clark died of natural causes in 2023 at age 66, according to police. Authorities have notified both victims’ families, who have asked for privacy, as well as Clark’s, who have cooperated with investigators, Petrosky said. Investigators have not determined whether Clark had any prior connection to the victims, but Petrosky said he believes the man could’ve been responsible for additional killings. “I believe that once you’re a serial killer, you’re always a serial killer. I believe there could potentially be more (victims),” he said. While identifying Rush and Ritter’s killer is a great accomplishment, Petrosky said investigators’ work is far from over as they continue to dig into Clark’s past. “We don’t consider the cases hopeless, we always think there’s something there,” he said. “It’s not about us; it’s about the victims and their families.”
