Murder
The intentional killing of any human being by another human being is defined as Murder. It is thought of as a different type of crime than manslaughter, because a murder is planned in advance while manslaughter is a homicide that takes place in the heat of the moment.
A murder is said to be committed with malice, an intention of harming or killing another person. In most states, murder is considered to have to degrees, or levels.
First Degree Murder
A killing that is planned out in advance for the express purpose of causing the death of any person is First Degree Murder. It is this type of crime that is commonly referred to as being "cold blooded" because of its calculated brutality.
Second Degree Murder
This is a homicide that was committed with the intent of injuring and killing another person, but was not planned in advance. In this sense it is much like manslaughter because it generally happens in the heat of the moment.
Punishments
Second degree murder will most often result in a long term prison sentence. First Degree murder is often eligible for a verdict of life in prison, very likely without the possibility of parole, or even capital punishment. There are differing theories on whether or not issuing the Death Penalty for these cases is fair and just. Some argue the theory of "an eye for an eye" to claim that the murderer deserves to be put to death, while other insist that it is never acceptable to take the life a human being, even if that person has killed someone else.
When a judge is considering what type of punishment to issue following a guilty verdict in a murder case, one of the things they usually examine is the crime history of the person on trial. A person with a previous crime record is likely to receive a more severe punishment than someone without a criminal past. In some states any person who is convicted of murder who also had a previous conviction will be sentenced as a First Degree murderer regardless of the type of homicide that was committed.
Justifiable Homicide
There is one situation in which a murder is considered to be justifiable and therefore excusable. This involves an individual killing a criminal who is in the act of committing a felony, especially if the crime was one that put the individual at risk of personal harm or death. A law enforcement officer who kills a felon is also considered to have done a justifiable deed.