The patrol officers get an anonymous report of a crash, an accident, a suicide, so they find the scene, find the body, and fill out the basic paperwork. There are some questionable issues involved, but there are detectives to handle such things, so they cover the basics and pass the buck on to the detectives. The detectives come out and investigate. They take notes about the little inconsistencies and bring it back to the supervisors to discuss further exploring the issue and how the case should be tagged. The supervisors talk to them about how to wrap this one up, it's just some poor bastard, we've got a lot of crime right now, remember that baby that went missing last week, we don't have resources to scan and test everything for every time one of these things happens. The supervisors talk to the chief, the mayor, the liaisons. There are a lot of people like this having those kinds of problems, getting this kind of treatment and dealing with these kinds of issues.
At no stage does anyone have to make an independent decision to marginalize something. Surrounded by a group, following the rules, the procedure, we're all shielded from having to feel that it's our decision to dig deeper or to not dig deeper. The patrol officers can think that they don't have the experience, expertise, or just the budgets or facilities that the detectives have. The detectives can think that they weren't the first on the scene, and anyway, they don't have the discretionary authority to alter the department's focus. The higher administrators can think that they haven't even seen the thing, and they have to make the tough decisions between what gets focused on and what doesn't, it's something they do every day, so a car wreck or a suicide or a non-celebrity drug interaction gets shelved in favor of searching for that one dude who's committing rapes on the east side, and if there really was anything suspicious about the car wreck or suicide or non-celebrity drug interaction, then the detectives surely would've made it a priority.
Of course, the detectives don't make it a priority, because they're exonerated from that responsibility by the pressure from above--the same administrative pressure that is relying on the detectives' necessarily blase approach to justify closing files.
The structures we use protect us from having to discover what we've done. Even the thug who set it up doesn't need to know what he's done. He switched some pill bottles for some bigshot, so what? The bagman told the thug to switch the pills, and to save face, acted like he knew it was for a good reason, because you have to instill respect for the organization. The organization's higher-up even thinks it's not his fault. Yes, he suggested that somebody needed to be sent a message, and yes, it's possible his associates may've gone a little overboard now and then, but you can't control that, and besides, the other side is probably playing the same game, and the whole world would come crashing down if we couldn't maintain any stability around here. The hospitalist who procured the pills doesn't know where they're going, probably some sick old person who's suffering and it's a humanitarian act to get the pills out the door. Like loading one of the rifles on the firing squad with blanks, everyone is blessed with plausible deniability of maybe not being the one who carried out the killing. "It wasn't really me."
Conspiracy doesn't require that very many people know what's going on. Conspiracy rests upon fifty people, ten people, one person, motivated by a general sense of purpose, utilizing a structure designed for irresponsibility. It doesn't take "a cover-up at the highest levels" to fail to investigate that unfortunate late-night car crossing the median or non-celebrity drug interaction, merely an accumulation of people who believe, at each step of the way, that their due diligence is but a small part of other people's due diligence.
It's a bit like the factory system. In theory, reducibility should produce the same finished product, but in fact, the efficiencies of subdivided due diligence cause each person to be less invested in the finished product. The master crafters who work all stages "by hand" (individualized attention to the parts and the whole) produce better trees and better forests, because the finished product is more than the sum of its physically verifiable operations. When it comes to managing a well-meaning dystopia, though, the factory system works in favor of evil, for it allows a thousand well-meaning actors--a thousand law enforcement officials who would not agree to participate in covering up a murder--to harmoniously delegate away their inner guilt at not pursuing what they should pursue. A hundred financial auditors work in concert with twelve Congressmen to free the big banks, not because they were outright bribed, or even indirectly bribed, but because their function, the "scope of their representation," if you will, is designed to produce a constant rationalizing of passive absorption, not unlike a television user, except one spread across several brains occupying several cubicles at the SEC.
The failure to recognize these mass effects--the butterfly cluster, rather than the butterfly--deludes many of us into being unable to conceive of an effect that is not explicitly guided by a group of cackling vampires. To be sure, there are groups of cackling vampires, but the greater part of their work is played out through the butterfly clusters of those of us who need avert our gazes with mere sub-microscopic subtlety, in order to produce, in the aggregate, the n=1 lack of understanding that prevents us from conceiving that any substantial group of people could have been utilized to achieve a private end.