Genetic geanology has enabled police in Northern California to pinpoint a suspect in the murder and rape of a teenage girl in 1982.
The Cloverdale Police Department announced on July 22 they have arrested Willows resident James Unick, 62, and charged him with the murder of Sarah Greer, 13 at the time. Unick was charged with Murder, Rape, Kidnapping, and Lew and Lascivious acts with a minor under 14-years-old by force.
"Today represents a bittersweet victory for justice,” Cloverdale Police Chief Chris Parker said in a statement. “While nothing can undo the pain inflicted upon the Geer family and our community, we can finally offer some solace in knowing that the perpetrator will be held accountable. This arrest is a testament to the dedication of our law enforcement agencies and the unwavering resolve of Cloverdale's citizens.”
Greer's body was found in the downtown section of Cloverdale on the morning of May 24, 1982. It was suspected that Greer was abducted and raped.
At the time of the murder, investigators collected DNA from the crime scene. They collected and preserved samples of blood and other fluids from Greer's body.
However, limitations in DNA technology made it difficult to identify a suspect.
While the case remained cold for the better part of four decades, officials reopened the murder investigation in 2021 with the help of both the Cloverdale Police Department and a private investigator.
And in recent years, investigators have developed a massive DNA database through consumer kits for DNA trait and heritage tracking that enables police departments to compare evidence to DNA and examine databases of suspects, defendants and convicted criminals ordered to submit DNA that allow police to find close DNA matches to potentially identify relatives.
"A male DNA profile was identified from the evidence and through the use of modern DNA genetic genealogy technology," the department said in a statement to NBC News.
While this technique does not result in investigators finding an exact match, it will allow them to identify a match from a group of siblings or other relatives. This is commonly known as DNA sleuthing.
The breakthrough came when investigators were able to identify a male DNA profile by examining the evidence and using modem DNA genetic genealogy technology.
“You get a pool of people and chip away at the folks who are there,” Parker said. “Then you investigate and see if they were alive, if they had the ability to commit the crime, if they were of age.”
Unick is being held without bail in Sonoma County jail.