August 19, 2026. A man named Kelly Lee Brower was arrested in Cottonwood, Arizona, on a capital-murder charge. The crime he allegedly committed happened forty-five years earlier. A woman was twenty-three years old when she was last seen walking home from a local bar. Two days later, children found her body in a field. She had been sexually assaulted and beaten to death. For more than forty years, the case stayed open. All previously known suspects were eliminated. The file sat. And yet the evidence survived. That survival is the entire story. Last lecture, we established that the Identity Silhouette — the convergence of behavioral analysis, spatial data, and DNA — is a hypothesis that physical evidence must confirm. Now the question is: what confirmed it here? The answer is a chain of linked stages, each one dependent on the one before it. Evidence preservation made the chain possible. Then laboratory reanalysis. Then genealogical research. Then conventional investigation. Then confirmatory testing. Remove any link, and the chain breaks. The case was identified in late 2020 as eligible for the Sexual Assault Kit Initiative (SAKI), a program that supports the inventory, testing, and investigation of backlogged sexual-assault evidence. This initiative, funded by the U.S. Department of Justice, exemplifies how policy changes can reopen cold cases. Think of the DNA work as a relay, not a sprint. In 2021, a forensic laboratory obtained a male DNA profile from critical evidence. The quantity was initially too small for genetic-genealogy testing. But the laboratory's work still produced something: a surname lead. The name Brower, and its possible variations. That partial result sat until 2025, when additional analysis of the remaining DNA was conducted, and forensic investigative genetic genealogy was used to identify a possible suspect. The lead pointed to Kelly Lee Brower, living in Arizona. Investigators then obtained a reference sample from a discarded beer can outside his residence. That sample matched DNA from Herrera's fingernail clippings. The reported random-match probability was at least one in 31 billion. Authorities reported Brower subsequently confessed. As of the arrest, the public record describes an accusation and a confession — not a completed trial or final judgment. Here is the failure mode that almost no one talks about, Tina. Closing a case is not the same as preventing the next one. The Resolution Trap assumes that solving a case automatically leads to systemic learning, which is often not the case. The Herrera investigation remained publicly listed as unsolved for years even though investigators retained biological evidence capable of later testing. That gap — between what the file said and what the evidence could do — is exactly the kind of gap that creates tomorrow's cold cases today. Reported cumulative SAKI results include more than 39,000 DNA profiles uploaded to CODIS and more than 19,000 CODIS hits. That scale means the Herrera case is not an outlier. It is a pattern. And patterns require systemic responses, not case-by-case heroics. The key idea is this: investigative decisions that cannot be explained later can become future investigative obstacles. A disciplined case-file audit operationalizes that principle. It requires that agencies document not just what evidence was collected, but why certain leads were excluded, what technologies were unavailable at the time, and what the file's known gaps are. For example, suppose an investigator chose not to preserve a secondary sample because the primary sample seemed sufficient. That decision, undocumented, looks like negligence years later. Documented, it becomes a recoverable data point. The SAKI model exemplifies interdisciplinary collaboration, requiring not just laboratory testing but also supporting investigation, prosecution, victim services, and case tracking. Documentation is not administrative overhead. It is the infrastructure that makes future forensic advances usable. Now, that audit approach can be applied across four domains. Archives: flag files where documentation gaps cluster around a specific witness type or location. Evidence lockers: confirm biological samples are stored under conditions that preserve DNA viability, and log storage conditions with dates. Database records: document CODIS submissions, results, and any subsequent genealogical steps taken or not taken. Interview files: note when accounts were obtained and flag any known post-event information exposure. [emphasis] Remember — the Herrera case succeeded because the evidence survived and the chain of custody held well enough for later technology to work. The preservation-and-documentation themes from this course point to the same operational truth. Preservation is strategy. Documentation is strategy. Waiting is not. The lesson is this: early investigative decisions shape what future investigators can do. Forensic genetic genealogy is an emerging technology with real scientific, legal, and ethical considerations. Federal guidance is explicit — it generates leads, not verdicts. Privacy and civil-liberties interests must be balanced against investigative need. That tension does not disappear because the outcome was just. Tina, the Yolanda files are not a story about a single breakthrough. They are a story about forty-five years of preserved possibility. The Systemic Audit Rule emphasizes proactive auditing of archives, lockers, databases, and witness files to prepare for future technological advancements. Because the next Yolanda Herrera deserves an investigator who already did the work.