What is Voluntary and Involuntary Manslaughter?

Manslaughter is divided into involuntary and voluntary manslaughter in Australia. The main difference between the two is the level of criminality or culpability inherent in the nature of the crime. Voluntary manslaughter generally attracts a greater sentence than involuntary manslaughter. But there have been cases where involuntary manslaughter has attracted a heavier sentence than voluntary manslaughter. This depends on the features of each case.

The crime of manslaughter carries up to 25 years imprisonment in New South Wales, prescribed by section 24 of the Crimes Act 1900 (NSW).

This article is intended for guidance, not legal advice. For legal advice, we encourage you to get in touch with our murder defence lawyers.

Involuntary Manslaughter | What is Involuntary Manslaughter?

Involuntary manslaughter is manslaughter by unlawful and dangerous act, or criminal negligence manslaughter. Each involve the causation of death to a victim but done by different means of offending conduct carrying a maximum penalty of up to twenty-five years of imprisonment in the state of New South Wales.

Involuntary Manslaughter by unlawful and dangerous act occurs when you commit an act causing death of a person; being conduct that substantially contributed to that death; and you intended to commit the offending act; your act was unlawful; and it was dangerous in the sense that a reasonable person in your shoes would realise that it exposed the deceased to a risk of serious injury in those circumstances at the time of the offence.

Manslaughter by criminal negligence occurs when you owed a legally recognised duty of care to the deceased; your voluntary act or omission was the substantial cause of the death (or substantially accelerated the death); and your actions or omission breached your legal duty of care because you failed to exercise the standard of care that a reasonable person in your shoes would have exercised in those circumstances at the time, or you did what a reasonable person in your position would not have done in the same circumstances; in addition, your act or omission caused criminal negligence warranting criminal punishment for manslaughter because if fell so far below the standard of care that a reasonable person would have exercised in the circumstances and was such a great risk that death or at least a really resinous bodily injury would be caused, that it deserved criminal punishment.

Voluntary Manslaughter | What is Voluntary Manslaughter?

Voluntary manslaughter is manslaughter by provocation, substantial impairment by abnormality of the mind, or excessive self-defence. Each involve the causation of death to a victim but done by different means of offending conduct carrying a maximum penalty of up to twenty-five years of imprisonment in the state of New South Wales.

Manslaughter by provocation is also called manslaughter by extreme provocation. This occurs if you commit murder; and your conduct causing death to the now deceased person was in response to the deceased’s conduct when he/she was alive; and the deceased’s conduct towards you at the time was the commission of a crime carrying up to at least 5 years imprisonment; and the deceased conduct caused you to lose self-control while in an emotional state (not a deliberate vengeful, revenge, or hatred act); and your conduct in those circumstances could have possibly caused an ordinary person to lose self-control to the same extent of intending to kill or inflict really serious injury.

The “ordinary person” under the law is considered someone with minimum powers of self-control expected of an ordinary citizen who is sober, of same age and maturity as the offender.

An offender who has voluntarily consumed alcohol and was thereby intoxicated at the time of the offence is not permitted to rely on intoxication when the court determines whether an ordinary person would possibly have lost self-control in the way the offender did.

Extreme provocation does not apply to conduct causing death that was in response to non-violent sexual advances.

Extreme provocation equally does not apply to conduct causing death that was committed after the offender has incited the deceased person to commit conduct in order for the offender to give him/herself an excuse to use the violence against the deceased.

Manslaughter by substantial impairment by abnormality of the mind occurs if your conduct causes the death of another person; your capacity to comprehend or understand the events or to judge as to whether it was right or wrong, or to control your conduct, was ‘substantially impaired by an abnormality of the mind; and the abnormality of the mind was caused by an underlying condition you already have, being a pre-existing physiological or mental condition which does not have to be permanent; and the impairment was substantial enough that it warrants liability for the murder to be reduced to manslaughter.

The offender’s state of intoxication at the time of the offending is not taken into account in determining this. This means that an offender cannot rely on voluntary intoxication as a defence.

Manslaughter by excessive self-defence occurs when you use force causing another person to die; being force under a belief that it was necessary to protect yourself from the deceased person; and a reasonable person in your shoes would believe that the force used was unreasonable in the circumstances you perceived at the time or would consider that your response was excessive.

Importantly, an offender cannot rely on his or her state of voluntary intoxication for purposes of considering whether the offender’s response was a reasonable response to what the offender perceived at the time in the circumstances. Intoxication can only be used and relied upon for determining the offender’s honest belief that his or her actions were necessary for purposes of protection.

Voluntary manslaughter examples include, circumstances a person commits an act causing death for purposes of protection but the response is not considered reasonable in the circumstances, because it is excessive. Another example is if a person commits an act causing death of another person but the offender’s capacity to understand or judge whether it was right or wrong, or to control his or her actions was substantially affected by an abnormality of the mind such that it was so substantial that it warrants the murder to be manslaughter.

Why is Voluntary Manslaughter Called Voluntary Manslaughter?

Voluntary manslaughter is called voluntary manslaughter because it involves a different level of criminality than involuntary manslaughter. Voluntary manslaughter is occurs either by excessive self-defence, extreme provocation, or substantial impairment by abnormality of mind.

Difference Between Voluntary and Involuntary Manslaughter

Voluntary manslaughter is murder except it’s criminality is reduced because it occurs in circumstances of extreme provocation, substantial impairment by abnormality of mind, or excessive self-defence. In comparison, involuntary manslaughter is also murder except that it occurs by unlawful and dangerous act, or criminal negligence manslaughter. The maximum penalty for each remains the same. Click here for information on manslaughter vs murder.

Defences to Manslaughter Charges

If a defence successfully applies to a manslaughter charge, it will result in an acquittal or dismissal of the charge.

Manslaughter defences include self-defence; mental illness defence; where the death was caused by an intervening occurrence; and involuntary consumption of drugs or alcohol affected your ability to form the intent required to commit manslaughter.

The most common types of defences run in manslaughter trials are self-defence or mental illness defences.

Mental Illness Defence for Manslaughter

There are two types of defences concerning mental illness, namely, either sane or insane automatism. Criminal responsibility does not attach to an involuntary act committed in a state of automatism whether or not the state of automatist is caused by a disease of the mind, or a mental health condition or cognitive impairment of the type required under section 28 of the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW) (‘MHCIFP’).

An act is committed in a state of automatism if you did an act without being conscious of the nature of it, and without being able to choose to commit it.

If evidence points to (establishing a reasonable possibility) you committed an act in a state of automatism from something other than a disease of the mind or a mental health condition or cognitive impairment under section 28 of the MHCIFP, then it displaces the legal presumption of voluntariness, then you will be acquitted of the manslaughter charge if the prosecution fails to prove beyond reasonable doubt that your actions were voluntary. This is the defence of sane automatism.

Examples of sane automatism include sleepwalking, post-traumatic loss of control from a head injury, and some types of epilepsy.

If evidence establishes that, on the balance of probabilities, you committed an act in a state of automatism from a mental health condition or cognitive impairment, or a disease of the mind (where you did not know the nature or quality of your act, or did not know that it was wrong), you will receive a special verdict of not criminally responsible pursuant to Part 3 of the MHCIFP. This is also known as the common law defence of M’Naghten rules. This is the defence of insane automatism.

If you receive a special verdict of not criminally responsible, which only applies to cases dealt with in the District or Supreme Courts of New South Wales, then the court may, amongst other options, either detain you in a mental health facility until released by due process of law or release you with or without conditions.

Unless you are released without conditions, you will be referred to the Mental Health Review Tribunal where you will become a forensic patient subject to reviews by the Tribunal for your continues detention, release, care and treatment every six months.

Unfortunately, a forensic patient can be detained for an indeterminate period of time. For this reason, the defence of insane automatism is not very attractive to most defendants facing manslaughter allegations.

Examples of insane automatism include psychotic disorder, bipolar disorder, substance induced mental disorder that is not temporary, and autism spectrum disorder.

Self-defence in Manslaughter Cases 

You will not be criminally responsible for a manslaughter charge if your conduct that caused the death falls within section 418 of the Crimes Act 1900 (NSW). This is the self-defence provision that apply if you did the alleged offending conduct to protect yourself in the circumstances you perceived to be in at the time, and further, if that response is considered reasonable in the circumstances you perceived it to be at the time, not that of the hypothetical reasonable person. Self-induced intoxication is not a relevant consideration when considering the reasonableness of the response that caused the death.

Factors that are relevant in considering the reasonableness of your response include, but not limited to are your age, health and strength, gender, and past experience.

Involuntary Manslaughter Sentence

The maximum penalty that the Supreme Court can impose on an offender guilty of manslaughter in New South Wales according to section 24 of the Crimes Act 1900 (NSW) is up to 25-years imprisonment.

An assault causing death when intoxicated carries a mandatory minimum sentence of not less than 8 years imprisonment, and it also attracts a non-parole period of not less than 8 years.

Manslaughter does not have a standard non-parole period unlike murder. The sentence one receives for a manslaughter offence will not normally be the maximum 25 years in jail. In fact it will usually be less, and dependant on the features of the case. Cases are like fingerprints, as each are unique in one way or another.

Other factors relevant in determining the sentence for manslaughter include the objective seriousness of the actual offence unique to the case. The more violence involved, the higher the objective criminality and therefore the greater the sentence is likely to be.

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