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Unraveling the Mystery: The Nancy Bennallack Case Finally Solved

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Prosecuting Cold Cases Using DNA Technology
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The world of cold cases is filled with unanswered questions and lingering mysteries. One case that haunted the Sacramento County community for decades is that of Nancy Bennallack.

Nancy was a vibrant young woman who was tragically murdered in 1970. Despite the tireless efforts of law enforcement, the case eventually went cold. In 2004, investigators reopened the case and obtained a DNA profile left by the killer at the crime scene. Staff entered the DNA profile into the Federal Bureau of Investigation’s Combined DNA Index System (CODIS). CODIS is an extensive national DNA database to help search for potential leads. Unfortunately, this search generated no leads, and the case again went cold. The lack of leads left her family and the community in shock and anguish; the killer remained unidentified, and justice seemed elusive.

"This case went unsolved for over 50 years. Over that timeframe, many new advancements in forensics were used in this case, which led to the DNA profile developed from the suspect’s blood left at the scene. Staff then uploaded the DNA into CODIS in 2004, and the DNA profile was run through the California Department of Justice Familial Search five times between 2009 and 2021—each with negative results," said Sacramento County Chief Deputy District Attorney Scott Triplett.

Then, in 2021, the Sacramento County District Attorney’s Office was awarded the Prosecuting Cold Cases Using DNA grant from the Bureau of Justice Assistance (BJA). Through this program, jurisdictions can access funding and technical assistance to increase investigative activities and crime and forensic analyses to support the prosecution of violent crime cold cases. With this award, Sacramento could redouble its efforts in solving Nancy’s murder.

Investigators turned to forensic genetic genealogy (FGG) to unlock the answers that had eluded them for decades. FGG is a term used to describe an investigative tool comprised of two main steps: first, a specialized DNA test designed to better identify distant relatives when searched against public family tree/ancestry databases, and second, a subsequent investigation focused on the genealogy of the genetic family associations identified in the first step.

In 2019, the DNA profile of the suspect in Nancy’s case was uploaded to publicly accessible genealogical databases, and extensive genealogical research and family tree-building commenced over two years. Investigators finally identified a potential suspect after overcoming significant challenges in building the family tree.

The potential attacker was identified as Richard John Davis, who had resided in the same apartment complex as Nancy at the time of her murder. Unfortunately, Davis was deceased, and his body was cremated; however, investigators identified a family member of Davis who cooperated and provided a DNA sample that confirmed Davis as the suspect. The lead investigator informed Nancy’s remaining family, and the case was closed. Although this conclusion of the case will not bring the perpetrator to justice, it offers a sense of closure and healing for Nancy’s family and the community.

The closing of Nancy’s case highlights the significance of DNA technology advancements and FGG’s potential in solving cold cases. It also serves as a testament to the dedication and perseverance of criminal justice agencies who work tirelessly to bring justice to victims and closure to their families.

“Solving cold cases is a joint effort—from laboratory personnel to investigators and attorneys to funding partners. BJA provides a key part of the equation. Not only is the grant a way to assist with funding, but it is also a network of organizations doing the same work, providing advice from lessons learned, and providing assistance when your case crosses jurisdictional lines.” — Scott Triplett

As communities continue to witness the power of DNA technology to solve crime, BJA hopes to help more communities consider applying for its forensic grants. To learn more about Prosecuting Cold Cases Using DNA or to apply, visit bja.ojp.gov.

Date Published: September 25, 2023