Updated October 2026 | The Bulldog Law | California Homicide Defense

Involuntary manslaughter is an unintentional killing caused by criminal negligence. Penal Code 192(b) defines it as the unlawful killing of a human being without malice, either in the commission of an unlawful act that is not a felony, or in the commission of a lawful act that might produce death, done in an unlawful manner or without due caution and circumspection. The person did not mean to kill and did not consciously disregard a known risk of death, which would be murder; they acted, or failed to act, with a gross lack of care that a reasonable person would have recognized as dangerous to life. The sentence is two, three, or four years, it is a felony that cannot be reduced to a misdemeanor, probation is available, and it is the lowest rung on the ladder of criminal homicide. Deaths caused by driving are excluded and charged as vehicular manslaughter instead.

The Bulldog Law's homicide attorneys see involuntary manslaughter in two roles. It is the charge in cases where no one disputes that the death was an accident but the prosecution says the accident was criminal: a firearm that discharged while being handled, a child or a dependent adult who died of neglect, a fight that ended in a fall, a drug a friend supplied, a workplace or recreational death. And it is the target in murder cases, where the difference between conscious disregard and negligence is the difference between 15 years to life and a term with an end. What follows is the statute and its two theories, what criminal negligence means, the fact patterns, the duty-to-act rule, the sentence and its consequences, and the defenses. Call (888) 928-1609 or message our team.

The statute and the two theories

Penal Code 192(b) contains two routes to the same crime, and the jury instruction, CALCRIM 580, sets out both. The first is the unlawful-act theory, sometimes called the misdemeanor-manslaughter rule: the defendant committed a crime that is not a felony, or committed a felony that is not inherently dangerous, and the way the defendant committed it was dangerous to human life under the circumstances, and it caused the death. The underlying act need not be dangerous in every case; a misdemeanor battery, a reckless discharge of a firearm, an illegal sale, or a violation of a safety regulation qualifies when the circumstances made it dangerous. The second is the lawful-act theory: the defendant did something lawful, but did it with criminal negligence, and it caused the death. Handling a gun, supervising a child, operating equipment, administering a substance, or caring for a dependent person are lawful acts that become involuntary manslaughter when done with gross carelessness.

Both theories require that the defendant's conduct caused the death, directly or as a natural and probable consequence, and that no independent intervening cause broke the chain. Our Penal Code 192 defense page covers all three subdivisions together, and our comparison of manslaughter and murder covers the line above.

What criminal negligence means

Criminal negligence is the heart of the offense, and it is more than carelessness. The instruction defines it as acting in a reckless way that creates a high risk of death or great bodily injury, where a reasonable person would have known that acting in that way would create such a risk; it is conduct so different from the way an ordinarily careful person would act in the same situation that it amounts to disregard for human life or indifference to the consequences. Three comparisons locate it. Ordinary negligence, the standard in a civil wrongful death case, is the failure to use reasonable care, and it is not enough for a conviction; a momentary lapse that a careful person might also have made is a civil matter.

Criminal negligence requires a gross departure. And conscious disregard, the standard for implied-malice murder, requires that the defendant actually knew the conduct was dangerous to life and deliberately acted anyway; criminal negligence is measured objectively, by what a reasonable person would have known, so a defendant who did not appreciate the risk can still be guilty of manslaughter but not of murder. 

Our discussion of negligent homicide covers the negligence standard in more depth. The practical dispute in most cases is whether the conduct was gross enough, and it is decided by the specific facts: the danger of the activity, the defendant's training and experience, the warnings available, and what the defendant did to reduce the risk.

The fact patterns

Involuntary manslaughter charges cluster in a few recurring situations. Firearm handling deaths, where a gun believed to be unloaded discharged, or a gun was handled while intoxicated, or a loaded firearm was left where a child found it, are charged on either theory, often alongside Penal Code 25100 criminal storage. Fights and shoves that caused a fall and a fatal head injury, where the defendant intended a battery but not a death, are charged on the unlawful-act theory, and the question is whether the battery was dangerous under the circumstances. Parental and caregiver neglect, where a child or a dependent adult died of starvation, untreated illness, or lack of supervision, is charged on the lawful-act theory with the duty discussed below, often with Penal Code 273a child endangerment or 368 elder abuse as companion counts.

Drug furnishing deaths, where the defendant supplied the substance that killed, are charged on the criminal negligence theory, and have increased sharply with fentanyl; the person who called for help is protected by the Good Samaritan law from a possession charge but not from manslaughter, and a person previously advised under Alexandra's Law faces murder. Workplace, construction, and recreational deaths, where an employer, operator, or guide disregarded a safety rule, are charged on either theory and are frequently accompanied by regulatory prosecutions. And a death that occurred during what the defendant claims was self-defense, where the force used was lawful but applied with gross carelessness, or where the self-defense claim fails on the reasonableness of the belief, can be charged as involuntary rather than voluntary manslaughter depending on the intent. Deaths caused by driving are excluded from 192(b) entirely and charged under Penal Code 192(c) or, where the driver was impaired, Penal Code 191.5.

Failure to act: the duty rule

A person can commit involuntary manslaughter by doing nothing, but only when the law imposed a duty to act. The duty arises from a relationship, such as parent and child or spouse and spouse; from a statute, such as the child abuse reporting and care obligations; from a contract, as with a hired caregiver, a nurse, or a lifeguard; or from a voluntary assumption of care, as when a person takes charge of someone helpless and, by doing so, prevents others from helping. Where the duty exists, a criminally negligent failure to feed, supervise, obtain medical care, or remove a person from danger that causes death is involuntary manslaughter.

Where it does not exist, there is no crime: California, like most states, imposes no general duty to rescue a stranger, and a bystander who watches a drowning or a fatal overdose and does not intervene has committed no homicide, however the conduct is judged morally. The duty cases are among the hardest in the practice because they involve parents and caregivers who were overwhelmed rather than malicious, and the defense frequently turns on whether the failure was gross negligence or the ordinary failure of a person without resources, training, or support.

The sentence and its consequences

Penal Code 193(b) sets the term at two, three, or four years, with the middle term presumptive. The offense is a felony with no misdemeanor alternative, which distinguishes it from most other non-driving homicide offenses, but it is served under realignment in county jail rather than state prison in most cases, and probation with a county jail term is available and frequently granted where the negligence was momentary and the defendant has no record.

The offense is not listed as a serious or violent felony on its own, so it carries 50 percent conduct credit and is not a strike, unless the prosecution pleads and proves that the defendant personally inflicted great bodily injury on a person other than an accomplice or personally used a dangerous or deadly weapon, in which case it becomes a serious felony and a strike; that allegation is routine in direct-contact killings and absent in omission and furnishing cases. Personal use of a firearm adds three, four, or ten years. The conviction brings a lifetime firearm prohibition, restitution to the victim's family, and, for a non-citizen, likely treatment as a crime involving moral turpitude, which our immigration attorneys review before any plea.

Defenses

Involuntary manslaughter cases are defended on three fronts. The first is the degree of negligence: the defense presents the evidence that the defendant's conduct, while it ended in tragedy, was the kind of lapse an ordinarily careful person could have made, which is a civil wrong but not a crime, and that line is argued through the specific facts, the defendant's experience, and expert testimony on the activity. A death that was a true accident, during a lawful act done with ordinary care, is excusable homicide under Penal Code 195 and no crime at all.

The second is causation. The prosecution must prove that the defendant's conduct was a substantial factor in the death, and the defense investigates the medical cause, the victim's own conduct, the involvement of others, and any intervening event that was unforeseeable and broke the chain; in furnishing cases, the victim's own decision to consume, and the presence of other substances, are litigated, and in neglect cases, the underlying illness and the medical care available are. The third is the duty and the act: in an omission case, whether a legal duty existed at all, and in an unlawful-act case, whether the act was in fact unlawful and whether it was dangerous under the circumstances.

Where the prosecution has charged murder, the defense presents the evidence that the defendant did not actually appreciate the risk, which negates implied malice and reduces the offense to involuntary manslaughter; the jury is instructed on the lesser offense whenever the evidence supports it, and a plea to involuntary manslaughter is the common resolution of a second-degree murder charge built on recklessness rather than intent. A conviction is eligible for expungement after probation where probation was granted.

Frequently asked questions

What is involuntary manslaughter?

Involuntary manslaughter is an unintentional killing caused by criminal negligence or by an unlawful act that is not a felony. California defines it in Penal Code 192(b) as the unlawful killing of a human being without malice, in the commission of an unlawful act not amounting to a felony, or in the commission of a lawful act that might produce death, done in an unlawful manner or without due caution and circumspection. The person did not intend to kill and did not consciously disregard a known risk of death; they acted with a gross lack of care that a reasonable person would have recognized as dangerous to life.

What is the sentence for involuntary manslaughter in California?

Two, three, or four years in state prison under Penal Code 193(b), served in county jail under realignment in most cases. Involuntary manslaughter is a felony, not a wobbler, so it cannot be charged or reduced as a misdemeanor, but probation with a jail term is available and is granted in a substantial share of cases, particularly where the negligence was momentary and the defendant has no record. Personal use of a firearm adds three, four, or ten years. By comparison, voluntary manslaughter carries 3, 6, or 11 years and second-degree murder 15 years to life.

Is involuntary manslaughter a felony?

Yes, always. Penal Code 192(b) involuntary manslaughter is a straight felony punishable by two, three, or four years. It becomes a strike under the Three Strikes law only if the prosecution pleads and proves that the defendant personally inflicted great bodily injury on a person other than an accomplice or personally used a dangerous or deadly weapon, which is frequently the case in a direct-contact killing but not in a case of omission, furnishing, or supervision.

What is the difference between involuntary manslaughter and murder?

The mental state. Murder requires malice: an intent to kill, or an intentional act dangerous to life done with knowledge of the danger and conscious disregard for it. Involuntary manslaughter requires only criminal negligence: a reckless act, creating a high risk of death or great bodily injury, that a reasonable person would have known was dangerous, whether or not the defendant actually appreciated the risk. The gap between conscious disregard and negligent failure to appreciate is the gap between 15 years to life and 2 to 4 years, and it is the central issue in a large share of homicide cases.

Can you get involuntary manslaughter for giving someone drugs?

Yes. Furnishing a controlled substance is itself a felony, so the misdemeanor-unlawful-act theory does not apply, but a person who supplies drugs that cause a death can be convicted of involuntary manslaughter on the criminal negligence theory where the furnishing was done without due caution, and California courts have upheld such convictions. Since 2024, a person who has previously been advised in court that furnishing fentanyl can kill, under Alexandra's Law, can be charged with murder on a later furnishing death. The Good Samaritan law protects the person who calls 911 from a possession charge, not from manslaughter.

Can involuntary manslaughter be charged for a failure to act?

Yes, where the defendant had a legal duty to act. A parent who fails to feed, supervise, or obtain medical care for a child, a caregiver who neglects a dependent adult, or a person who assumed responsibility for someone helpless and then abandoned them can be convicted of involuntary manslaughter if the failure amounted to criminal negligence and caused the death. There is no general duty to rescue a stranger, so a bystander's inaction is not a crime; the duty arises from a relationship, a statute, a contract, or a voluntary assumption of care.

Related reading from our attorneys

• Manslaughter versus murder: the differences
• Negligent homicide and the criminal negligence standard
• Vehicular manslaughter under Penal Code 192(c)

A death that was an accident? Whether it was a crime is the question

The Bulldog Law's criminal defense attorneys defend involuntary manslaughter, murder, and child and elder neglect homicide cases across California, with the medical, forensic, and causation experts retained at the start. Call (888) 928-1609 or reach us online.

that cause a death can be convicted of involuntary manslaughter on the criminal negligence theory where the furnishing was done without due caution, and California courts have upheld such convictions. Since 2024, a person who has previously been advised in court that furnishing fentanyl can kill, under Alexandra's Law, can be charged with murder on a later furnishing death. The Good Samaritan law protects the person who calls 911 from a possession charge, not from manslaughter.