Explainers
Linkage Blindness: Why Some Murders Go Unsolved
Updated July 2026.
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 were long the textbook example — and are now a textbook example of the opposite. 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. What finally broke the case is exactly what had been missing: linkage. A 2022 inter-agency task force pooled records across departments, and cross-jurisdiction DNA and cellphone evidence — including DNA recovered from a discarded pizza box — connected the scattered killings to one man. On April 8, 2026, Rex Heuermann pleaded guilty to murdering seven women — the four originally known as the Gilgo Four (Melissa Barthelemy, Maureen Brainard-Barnes, Megan Waterman, and Amber Lynn Costello) along with Jessica Taylor, Valerie Mack, and Sandra Costilla — and admitted in court to killing an eighth, Karen Vergata, whom he was never separately charged with. On June 17, 2026, Suffolk County District Attorney Raymond Tierney’s office saw him sentenced to consecutive terms of life in prison without the possibility of parole. A series that had stayed cold for roughly thirteen years broke the moment the evidence was finally connected across jurisdictions. (When there is no direct DNA hit at all, cold cases are increasingly cracked by a related method, investigative genetic genealogy.) The lesson cuts both ways: whose victim it is should never decide the urgency of the search — and once the pieces are connected, even the coldest series can fall.
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, maintains the largest independent database of U.S. homicides — including the more than 250,000 killings since 1980 for which no one has ever been charged — and runs a publicly accessible algorithm over those records. The algorithm groups cases by geography, victim sex, and method and flags statistical clusters of unsolved murders with abnormally low clearance rates — often dozens of cases at a time, the kind of 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, only about 61.4% of murders were cleared in 2024 — meaning roughly four in ten went uncleared that year — so even setting linkage aside, a large share of killings are never resolved.
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.
Sources
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