Homicide is the killing of one person by another. At common law, homicide is classified in three ways:
Justifiable
homicide, is homicide that takes place in the reasonable belief that a
serious crime is being committed and in an attempt to prevent the
crime. It may also be in self-defense, in defense of others, or an
action taken in the line of duty, such as one by a police officer.
Someone who hits someone over the head to prevent the assailant from
raping a woman has committed homicide if the assailant dies, but the
homicide would be justifiable if the amount of force used was necessary
to prevent the crime of rape. A police officer who shoots and kills
someone who appears to be about to shoot a gun may also be justified.
Excusable homicide is homicide committed accidentally or with
sufficient provocation while doing some lawful activity. For example,
if someone is physically attacked in a parking garage and kills the
attacker while defending himself, that would be excusable homicide if
the attack victim did not use a dangerous weapon or kill in a cruel or
unusual way.
Criminal homicide is the unlawful killing of another. It is divided into several categories. See murder and manslaughter.