precisely - it clearly isn't murder
Involuntary manslaughter
Involuntary manslaughter is the unlawful killing of a human being without
malice aforethought, either expressed or implied. It is distinguished from voluntary manslaughter by the absence of intention. It is normally divided into two categories, constructive manslaughter and criminally negligent manslaughter, both of which involve criminal liability.
Constructive manslaughter
Constructive manslaughter is also referred to as "unlawful act" manslaughter. It is based on the doctrine of constructive malice, whereby the malicious intent inherent in the commission of a crime is considered to apply to the consequences of that crime. It occurs when someone kills, without intent, in the course of committing an unlawful act. The malice involved in the crime is transferred to the killing, resulting in a charge of manslaughter.
For example, a person who fails to stop at a red traffic light while driving a vehicle and hits someone crossing the street could be found to intend or be reckless as to assault or criminal damage (see DPP v Newbury
[9]). There is no intent to kill, and a resulting death would not be considered murder, but would be considered involuntary manslaughter. The accused's responsibility for causing death is constructed from the fault in committing what might have been a minor criminal act. Reckless driving or reckless handling of a potentially lethal weapon may result in a death that is deemed manslaughter.
Involuntary manslaughter may be distinguished from accidental death. A person who is driving carefully, but whose car nevertheless hits a child darting out into the street, has not committed manslaughter. A person who pushes off an aggressive drunk, who then falls and dies, has probably not committed manslaughter, although in some jurisdictions it may depend whether "excessive force" was used or other factors.