Voluntary manslaughter is the killing of a human being in which the offender had no prior intent to kill and acted during "the heat of passion", under circumstances that would cause a reasonable person to become emotionally or mentally disturbed. Voluntary manslaughter is one of two main types of manslaughter, the other being involuntary manslaughter.
Provocation consists of the reasons for which one person kills another. "Adequate" or "reasonable" provocation is what makes the difference between voluntary manslaughter and murder. According to the book Criminal Law Today, "provocation is said to be adequate if it would cause a reasonable person to lose self-control".
In some jurisdictions, malice can also be negated by imperfect self-defense. Self-defense is considered imperfect when the killer acted from his or her belief in the necessity for self-defense, but that belief was not reasonable under the circumstances. If the belief in self-defense were reasonable, then the killing would be considered justified and not unlawful. Where the belief is unreasonable, the homicide is considered to be voluntary manslaughter.
Intent to kill is normally present during a voluntary manslaughter case, but it is not required. Since most heat of passion and imperfect self-defense killings involve intent to kill, typical voluntary manslaughter involves intentional killings. However, there are occasions when intent to kill is not present, although malice is. One example of this would be when a person responds to oral provocation by engaging in physical altercation. The provocation is sufficient so that their response is justified. Should the response result in the death of the provoker, the crime is either voluntary manslaughter or second degree murder, depending on the jurisdiction.