Murder has become largely confined to the poor and disadvantaged whereas historical records show that in times gone past it was used equally by all levels of society.
This is taken from a 1997 study called ‘The Decline of Elite Homocide’, published in the journal Criminology, which attempts to explain how homicide has become less democratic over time.
The criminological literature consistently reports a negative relationship between social status and interpersonal homicide. Regardless of the setting studied, homicide tends, with just a few exceptions, to be concentrated among low-status groups, such as the poor, the unemployed, the young, and cultural minorities. Yet robust as it is, this relationship is confined to modern societies. In the premodern era, homicide was found at all levels of the social hierarchy, including its higher echelons.
What explains these facts? Why is homicide largely confined to low status people today but was not in the societies studied by anthropologists and historians? Why has elite homicide declined? The answer developed here builds on a theory advanced by Donald Black (1983), which argues that violent conflict is a function of the unavailability of law. In modern societies, low social status and law are antagonistic, and the result is that legal means of resolving conflict are effectively unavailable to those at the bottom of the social pyramid. In earlier societies, law tended to be unavailable to everybody, irrespective of their social standing.
Link to DOI entry and summary for study.
Mind Hacks 
I’m interested in hearing the research’s refutation of the (mis)perception that being wealthy affords the rich the ability to hide, litigate, or create deception that leads to murder cases being swept under the rug from public view (even perhaps the public view of determined investigation).
I might be implying a certain cliche, but it is the one immediate reaction I get when reading this abstract.
And see the contrasting meditations of McHeath and Peachum in “The Threepenny Novel” (Bertolt Brecht)
McHeath -“Brute force is out of date – Why send out murderers when one can employ bailiffs?”
Peachum – “Admittedly, murder is a last resort, the very last – but it is still useful”.
I wonder if this swing coincided with the prevalence of drug/alcohol prohibitions. I wonder also if richer people get drunk less in the close proximity of others.
I don’t think the rich get drunk less, but they may have a greater belief in their own ability to hurt others without actually touching anyone. It may not only be a case of the rich feeling that they can call on the law, or circumvent it if necessary. They may also believe they don’t need to physically engage in order to harm.
Lower economic status can be associated with the need to physically and personally deal out the hurt or the “justice”. I mean, really, there just aren’t enough rich people out there to make Chuck Norris THAT popular.