There is a difference between homicide and murder.
Most people use the words murder and homicide interchangeably, but they are not the same. Although murder and homicide are both used to describe the act of killing another human being, the circumstances surrounding the charges are different.
The easiest way to describe the differences between murder and homicide is that homicide is the killing of another human being, while murder requires the intent to kill another human being. Homicide can be used to describe any death where another person is at fault, but there are
mitigating circumstances that can influence the charge of homicide. When someone is convicted of murder, however, they are not only convicted of a homicide, but also the malicious intent to kill.
In the United States, we have terms like justifiable homicide and non-criminal homicide that are used to describe acts of homicide where there is no mens rea involved. The U.S. requires that the prosecution in a criminal trial prove both actus reus and mens rea in a criminal crime; the former translates as guilty mind and the latter refers to guilty act. Actus reus is simply the proof that a defendant committed a criminal act, while mens rea is a little more complicated. In order to prove mens rea, the prosecution must show that the defendant either had an intent to commit the crime or acted with criminal negligence.
With this in mind, you must understand that homicide is not always illegal, while murder is always illegal. For example, judicial homicide involves the use of deadly force by a law enforcement officer who must kill in order to save his life or the lives of others. Although judicial homicide is usually investigated by the Internal Affairs Bureau (IAB), criminal charges are not brought against the officer unless there is evidence that deadly force was unnecessary