Involuntary Manslaughter Laws Explained

Involuntary manslaughter refers to unintentional homicide that occurs either during the commission of non-felony crimes or during lawful conduct engaged in a reckless manner.

Legal Definition Of Involuntary Manslaughter

 Manslaughter is the unlawful killing of a human being without malice.  It is of three kinds: (b)

  • Involuntary – in the commission of an unlawful act, not amounting to a felony;


  • In the commission of a lawful act which might produce death, in an unlawful manner, 


  • Without due caution and circumspection.  This subdivision shall not apply to acts committed in the driving of a vehicle.

Involuntary manslaughter does not include death that occurs as a result of an act a defendant commits while driving a car.  In California, gross vehicular manslaughter  or negligent vehicular manslaughter and involuntary manslaughter are separate crimes with distinct definitions and punishments.1

Example: Kenneth prescribed a dose of insomnia medication to a patient that was significantly above the dose that was safe.  As a result, the patient died from an overdose.  Prescribing drugs is generally a lawful activity but in this instance, the state will have to prove that Kenneth acted recklessly by prescribing a dose that was not safe.  The state does not need to prove that Kenneth intended to kill the patient.

How Does The Prosecutor Prove Involuntary Manslaughter?

To prove that the defendant is guilty of this crime, the prosecutor must prove that2:

  • The defendant committed an unlawful act (not amounting to a felony)3 or a lawful act in an unlawful manner;
  • The defendant committed the crime or act with criminal negligence4; AND
  • The defendant’s acts caused the death of another person.

Proving “criminal negligence”: Criminal negligence involves more than ordinary negligence. A person acts with criminal negligence when:


In other words, a person acts with criminal negligence when the way he or she acts is so different from the way an ordinarily careful person would act in the same situation that his or her act amounts to disregard for human life or indifference to the consequences of that act.5

Who Can Be Charged With Involuntary Manslaughter?

Under Penal Code section 192(b), anyone who causes a death of another while acting with:

  • Criminal recklessness or
  • Negligence; or
  • Anyone who causes a death of another that, results during the commission of a misdemeanor or infraction can be charged with involuntary manslaughter.


Jeff politely asked the Kirk to switch the channel to the football game but was completely ignored.  Jeff then took out a gun, which is a misdemeanor under California’s brandishing a weapon law, planning merely to threaten Kirk to switch the channel.

But when Kirk saw Jeff displaying a weapon, he unexpectedly jumped at Jeff to try to grab the gun away from him.  As a result, the gun went off accidentally, killing Kirk.  Although Jeff did not have the intent to kill Kirk, the fact that Kirk was shot and killed while Jeff committed a misdemeanor, makes involuntary manslaughter the appropriate charge in this instance.

How Can You Fight Involuntary Manslaughter?

There are several defenses that your attorney can assert on your behalf to fight a charge of involuntary manslaughter.  Here are the most common ones:



  • Imperfect self-defense: A killing that would otherwise be murder is reduced to involuntary manslaughter if the defendant killed a person because he/she acted in imperfect self-defense or imperfect defense of another.  The difference between complete self-defense or defense of another and imperfect self-defense or imperfect defense of another depends on whether the defendant’s belief in the need to use deadly force was reasonable. 6


  • At least one of those beliefs was unreasonable.


  • Accidental killing: An accidental killing committed during lawful events does not meet the requirements of a murder.  However, if an accidental killing occurs during the commission of a crime, it could be considered murder.  Homicide is excusable when committed by accident, or in doing any other lawful act by lawful means, with usual and ordinary caution, and without any unlawful intent. 7





What Are The Penalties, Punishment And Sentencing Guidelines For Involuntary Manslaughter Under Penal Code 1929(b) PC?

Involuntary manslaughter is a felony and a defendant can face up to:

  • 1 year county jail OR
  • 2, 3, or 4-year prison sentence

Additionally, a defendant can face the following additional penalties:

  • Loss of the right to possess a firearm
  • A fee of up to $10,000

Related Offenses

Next Steps If You Need Help




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  1. Involuntary Manslaughter Defined. Penal Code 192(b); CALCRIM No. 581. []
  2. Elements. Penal Code 192(b); CALCRIM No. 581. []
  3. An “unlawful act” not amounting to a felony is either a misdemeanor or an infraction.  Unlawful Act Not Amounting to a Felony.  People v. Thompson (2000) 79 Cal.App.4th 40, 53 [93 Cal.Rptr.2d 803]. []
  4. Criminal Negligence Requirement People v. Butler (2010) 187 Cal.App.4th 998, 1014 [114 Cal.Rptr.3d 696].  “The words lack of ‘due caution and circumspection’ [in Pen. Code,  §192(b)] have been heretofore held to be the equivalent of ‘criminal negligence.’” People v. Penny (1955) 44 Cal.2d 861, 879 [285 P.2d 926]. []
  6. CALCRIM No. 581. []
  7. Pen. Code §195. []