One of the country’s oldest cold cases has been solved with the help of cutting-edge DNA forensics technology and evidence collected from an untested sexual assault kit.
Harold W. Carpenter, 63, was arrested in Spokane, Washington, on February 28 in connection with the brutal rape and murder of Patricia Carnahan, who was found beaten and strangled to death at a South Lake Tahoe, California, campground on September 28, 1979.
According to the El Dorado County, California, District Attorney’s Office, investigators gathered DNA and evidence from a sexual assault kit, but could not identify a victim or suspect at the time and the case went cold.
Over three decades later, Washington cold case detectives finally identified the victim and suspect thanks to advancements in genetic genealogy technology. In 2015, the cold case was revived by the El Dorado County Cold Case Homicide Unit after investigators released pictures of the victim’s jewelry to local newspapers.
Family members were able to identify a pendent that Carnahan often wore, and the family’s DNA was subsequently matched to the victim.
Fast-forward eight years, and Carpenter was identified as a prime suspect in the homicide when DNA from a sexual assault kit taken in Spokane in 1994 matched with the suspect’s DNA from the 1979 case. No charges were made in the 1994 crime, which was declared unprovable, but authorities said the DNA from that case was retested this year as part of Washington’s efforts to eliminate a backlog of untested sexual assault kits.
“He was not charged in that. So his DNA sat in a warehouse almost 30 years,” El Dorado County District Attorney Vern Pierson said.
The results were then entered into CODIS — the FBI’s Combined DNA Index System — and yielded a match with the Carnahan suspect.
“DNA and genetic genealogy is a big deal,” Pierson said after the finding.
According to Pierson, investigators came close to solving the Carnahan case in 2020 by comparing the suspect’s DNA with public family tree databases such as 23andMe. The results led investigators to Carpenter’s uncle, whom they interviewed, but no arrests were made at the time.
Carpenter was ultimately arrested three years after that due to the recent breakthrough and was held on a fugitive charge in the Spokane County Jail without bond. He is pending extradition to California on a murder warrant.
“This is one of the oldest cold case murders in the country to be solved through a sexual assault DNA review run through CODIS,” the El Dorado County District Attorney’s Office said.
The DA added that the case was the 13th solved by their cold case task force.
“I’m proud to say our Cold Case Unit is one of the most successful of its kind in the United States. Sadly, Ms. Carnahan was buried in a potter’s field under a headstone of an ‘unidentified female.’ Because of the tireless dedication of our investigators, she was identified and returned to her family,” Pierson said in a press release.
Carnahan was given a proper burial after being identified.
Washington Attorney General Bob Ferguson said the case was an example of the importance of testing sexual assault kits and filing evidence into CODIS.
“Every untested kit could be a potential break in a cold case,” Ferguson said in a statement. “Hard work and cross-state collaboration made this case successful. I’m grateful for the hard work from law enforcement to pursue justice in this case.”