Not to give too much away, but in our Byzantine mysteries the murderer is rarely turned over to the authorities. Rather, our detective, John the Lord Chamberlain to Emperor Justinian, usually finds some way to bring justice to the miscreants himself. This isn't merely an artistic decision on the part of the authors. In fact, for much of its history the Roman Empire lacked the criminal justice apparatus we take for granted. There were no official police forces, or prison system, and as for murder...well, there was no general law against it.
That surprising fact is one of many aspects of murder, broadly defined, dealt with in A Fatal Thing Happened on the Way to the Forum. Emma Southon discusses assassinations, murder within the family, murder by magic, and murder in the gladiatorial arena among other subjects. Although the book covers only the Republic and early Roman Empire the laws involved are not much different from those of Justinian's time.
And very strange they appear to us. Who in the twenty-first century would inscribe the following on a child's gravestone?
"To the spirits of the dead and to the most unfortunate Julia Restuta, murdered at the age of ten on account of her jewelry. Her parents, Julius Restutus and Statia Pudentilla, [set this up]."
This and other such epitaphs were likely the only "justice" average murder victims were likely to receive. Since murder was for centuries not a crime in the Roman Empire the responsibility for investigating, prosecuting and punishing a murder was entirely on the family and friends of the deceased. Unless a family was wealthy it had no way to pursue a murderer. The poor couldn't even afford a gravestone pointing a finger.
Roman law, at its inception in the Twelve Tables, was largely concerned with property rights. Perhaps because of the Ten Commandments we expect laws to have a moral basis but the Romans didn't think that way. Nor were they interested in interfering in family affairs. As Southon puts it: "The Roman state, at least until the dawn of the Imperial period, did not consider itself to be harmed, threatened or challenged when a man strangled his wife or stabbed a rival. That was their personal business."
Although we tend to think of the fellow on the library floor with the knife stuck in his back as the victim, technically the victim in a murder prosecution is the state. The state is the plaintiff. The state has suffered a challenge to its power to control the behavior of its citizens via the laws it has passed and thus it is the state that brings the case.
The Roman state was more interested in protecting private property than in protecting human life. Thus, while the family of a child killed in a mugging had no recourse, a man whose slave was murdered -- the slave being property and no more a human being than a table -- was at least reimbursed for his loss at market value just as he would have been for the destruction of cattle.
To the extent that Roman law dealt with murder it was through a hodge podge of provisions designed to deal with specific situations without apparent reference to any general concept of morality. For example, the father had absolute control of his family. Therefore infanticide was legal, however there was a law against parricide. This killing of any ancestor must have struck the Romans as particularly heinous -- as opposed to leaving an unwanted baby on a rock -- because the miscreant was put into a sack with a dog, a cockerel, a monkey and a snake. And then the sack was thrown into the sea. Did the phrase cruel and unusual spring to mind? (And where was the ASPCA?)
Many authors like to draw parallels between past events and today based on the supposition that human nature hasn't changed through the ages. And yet, looking at history from a modern perspective it is easy -- too easy -- to interpret the past in light of the present, to assume that people long dead had exactly the same motivations and goals and thought processes we do. Given our prejudices it is sometimes more difficult to see the differences between us and our ancestors than it is to see the similarities. A Fatal Thing Happened on the Way to the Forum is not only a fascinating look at murder in all its forms during the Roman Empire, it is also an excellent antidote to the tendency to describe the past as the present but without cell phones.