Explainers
Why Do Some Murders Go Unsolved? Linkage Blindness and the Victims We Overlook
Many murders go unsolved not because the evidence isn’t there, but because no one connects the dots. When related killings happen in different counties or states, the agencies investigating them often never learn the others exist — a documented failure investigators call linkage blindness. Add the long-standing tendency to under-investigate marginalized victims, and you get cases that stay cold for decades while a pattern hides in plain sight. Here is how that happens, and what is finally being done about it.
What linkage blindness actually is
American policing is intensely local. A homicide in one county is investigated by that county’s detectives, logged in their records, worked with their resources. If the same offender kills again two counties over — or two states over — those detectives are usually working in the dark, unaware that a strikingly similar case exists elsewhere. There is no automatic national tripwire that says, “these belong together.”
That gap has a name. Linkage blindness is the failure to recognize that separate crimes are connected. It is not a story about brilliant criminals outwitting the system; far more often it is a structural problem — fragmented records, jurisdictions that don’t share data, and the sheer volume of cases. When linkage fails, a series gets worked as a scatter of unrelated incidents, and the thread that would crack all of them is never pulled.
Why some victims fall through the cracks
Linkage blindness is worse for some victims than others. Cases involving people on society’s margins — those in the sex trade, people struggling with addiction or homelessness, those who are transient or estranged from family — have historically drawn less investigative urgency. When a victim is presumed to be “high-risk” or simply isn’t missed quickly, the early hours that matter most can slip away, and the case can be quietly deprioritized.
The Gilgo Beach murders on Long Island became the textbook example. For more than a decade, the cases of women who had disappeared after arranging to meet clients online were treated separately, under-investigated, and in some instances barely investigated at all — a failure many critics tied directly to the fact that the victims had worked in the sex trade. A killer operated for years in the gap. Only after a 2022 inter-agency task force finally treated the cases as worth solving did the forensic and digital trail come together. The lesson is uncomfortable and central to honest true-crime work: whose victim it is should never decide the urgency of the search.
How public data is starting to catch what humans miss
The encouraging development is that the systemic gap can be measured. Independent analysts have begun using public homicide data to find clusters that humans missed. The Murder Accountability Project, a nonprofit founded in 2015 by retired detectives, journalists, and scholars, runs a publicly accessible algorithm over decades of federal homicide records. It organizes more than 700,000 killings into roughly 100,000 groups by geography, victim sex, and method, then flags clusters with abnormally low clearance rates — the statistical fingerprint a hidden series can leave behind.
Crucially, the project is careful about what its results mean. A suspicious cluster is a question, not an answer: the organization states plainly that these patterns “are not proof of the presence or absence” of a serial offender. The output points at cases and systems — here is a group of unsolved killings that share a signature and that nobody seems to be clearing — not at any individual person. That distinction is the whole ethical ballgame. Pointing a data tool at the gap helps victims; pointing one at a person risks branding the innocent, because true serial offenders are rare and any individual prediction is overwhelmingly likely to be wrong.
What it would take to close the gap
The fixes are not mysterious. They are cross-jurisdictional data sharing, consistent and complete homicide reporting, and — most of all — the discipline to take every victim seriously from the first day, regardless of who they were or how they lived. None of that is glamorous. All of it saves lives, because a pattern caught early is a series cut short.
Frequently asked questions
Why do so many murders go unsolved? A combination of factors: fragmented, local recordkeeping that makes it hard to connect related cases across jurisdictions (linkage blindness); the under-investigation of marginalized victims; resource limits; and cases that simply lack physical evidence. Nationally, a significant share of homicides go uncleared each year.
What is linkage blindness? It is the failure to recognize that separate crimes are connected — usually because the agencies involved don’t share records or aren’t aware of one another’s cases. It allows a single offender’s crimes to be worked as unrelated incidents.
Is there a tool that detects serial killers? There are tools that detect suspicious patterns in case data — most notably the Murder Accountability Project’s public algorithm, which flags clusters of unsolved killings with low clearance rates. They identify cases and systemic gaps that deserve a closer look; they explicitly do not identify or accuse individuals, and their developers stress that a cluster is not proof of a serial offender.
Why are marginalized victims more likely to be overlooked? Victims in the sex trade, those struggling with addiction or homelessness, and people who are transient have historically drawn less investigative urgency and are often not reported missing quickly — which both delays investigation and makes linkage across cases harder.
If you are reading this because of someone you lost, we are sorry. Every name matters, and no victim should be a lower priority than another. For support and resources, see our support page.