Definition and Classification
A homicide is defined as the killing of one human being by another. At common law, there were three classifications of homicide. There was justifiable homicide, excusable homicide and criminal homicide. Justifiable homicides were those homicides that were authorized by law and were, therefore, not punishable. Excusable homicides were those homicides in which the killer was to some extent at fault for the death, but because of other circumstances, prosecution for full blown criminal homicide was not appropriate. In these situations the homicide was in fact criminal but the penalty was reduced. Finally, criminal homicide was any homicide that was not justifiable or excusable. Typically, criminal homicides were characterized as either murder or manslaughter.
Modern statutes have changed these common law definitions. For example, under modern statutes, excusable homicides are no longer punishable at all, so that there is really no difference any longer between justifiable and excusable homicides. Further, where criminal homicide under common law only included murder and manslaughter, modern statutes include the category of negligent homicide in criminal homicide as well. Finally, modern statutes have divided murder into first degree murder and second degree murder, and, additionally, many jurisdictions have created a separate category of capital murder for which the death penalty may be imposed.