One of the most persistent myths about violent crime is that it most often comes from a stranger. A random attack. A predator lurking in an unfamiliar place. The reality is almost the opposite.
The overwhelming majority of homicides and violent assaults are committed by someone the victim knew. A partner, a family member, a friend, a neighbour. This is not a fringe statistic. It is one of the most consistent findings in criminology across decades of data.
And yet, investigative failures continue to happen in exactly these cases. Not because investigators do not know the statistics, but because knowing a fact and allowing it to shape your thinking are different things.
The Intimate Partner Problem
Cases involving intimate partner violence are among the most frequently mishandled in the criminal justice system. There are several reasons for this, and most of them have nothing to do with the competence of individual investigators.
When a victim has a prior relationship with their attacker, bias enters quietly. Why didn't she leave? Why did she let him back in? Was this really as bad as she says? These questions, whether conscious or not, shape the energy and resources that go into building a case. They shift focus from the perpetrator's behaviour to the victim's choices.
The result is that cases which should be treated as serious from the first call are sometimes filed away as domestic disputes, a phrase that carries an implicit dismissiveness, as if violence between people who loved each other is a different category of violence.
By the time investigators revisit these cases, if they ever do, critical evidence has been lost, witnesses have changed their accounts, and the window for prosecution has narrowed significantly.
When Family Is a Suspect and a Grieving Party
Cases where a family member is responsible for a victim's death present a different kind of investigative challenge. The people investigators most need to interview are also the people most likely to be actively misleading them, and simultaneously, the people who may be genuinely grieving.
This creates a dynamic that requires investigators to hold two things at once: compassion for loss, and scrutiny of the people closest to the victim. Not every investigator is trained to do this well. Some lean too far toward assuming grief equals innocence. Others adopt an adversarial posture so early that they alienate witnesses who might eventually have been cooperative.
Getting this balance right requires both training and supervision. When it goes wrong, cases collapse before they ever reach a courtroom.
Tunnel Vision and the Closed Mind
Perhaps the most damaging investigative failure in cases involving known perpetrators is tunnel vision: locking onto an early suspect or theory and filtering all subsequent evidence through that lens rather than following where it actually leads.
Wrongful convictions studies have identified tunnel vision as a factor in a significant proportion of cases. It is not usually the result of malice. It is the result of confirmation bias operating under pressure, the human tendency to find patterns and then defend them.
Cold case reviews have overturned convictions and identified entirely different perpetrators decades later because fresh investigators came to the evidence without the original tunnel. What they found was that the evidence had always pointed elsewhere. It simply had not been seen that way.
What Better Looks Like
Better investigations begin with fewer assumptions. They treat the victim as a full person whose life, relationships, and history deserve thorough documentation rather than selective attention. They pursue alternative theories even after a suspect has been identified. They involve oversight structures that catch tunnel vision before it closes a case in the wrong direction.
None of this is easy in the context of resource constraints and institutional pressure. But the families of victims whose cases went wrong because of these failures have paid a price no resource argument justifies.