Involuntary Manslaughter Lawyers (PC 192b)

A split-second lapse in judgment, a tragic accident, a moment no one can take back. Now prosecutors are calling it a crime.

Involuntary manslaughter is one of the most misunderstood charges in California criminal law. Unlike murder, it does not require any intent to kill. Unlike voluntary manslaughter, it does not involve a conscious decision to harm someone. What it does involve is an allegation that someone acted with criminal negligence, and that negligence caused another person’s death.

For working professionals, this charge often arises from situations that feel nothing like criminal conduct: an accidental firearm discharge at home, a workplace safety oversight, a moment of inattention while supervising a child. Good people find themselves facing felony homicide charges for what they experience as a devastating accident. The fear and confusion are real, but so are your defense options.

Our team at The Nieves Law Firm Criminal Defense Attorneys has defended clients facing the full spectrum of violent crime charges across the Bay Area. We understand how Alameda County prosecutors build these cases, and more importantly, we know where those cases break down. If you or someone you love is facing involuntary manslaughter charges, the earlier you bring in experienced defense counsel, the stronger your position will be.

Schedule a consultation to discuss your case with our team today.

How California Defines Involuntary Manslaughter

Under Penal Code section 192, subdivision (b), involuntary manslaughter is the unlawful killing of a human being without malice.¹ The statute specifically covers killings that occur:

• During the commission of an unlawful act not amounting to a felony, or
• During the commission of a lawful act performed in an unlawful manner, or without due caution and circumspection²

That phrase “without malice” is the defining feature. Prosecutors do not need to show that the defendant intended to kill anyone or even intended to cause harm. What they must show is that the defendant’s conduct crossed the line from ordinary carelessness into criminal negligence, and that the negligence was a substantial factor in someone’s death.

This charge is a felony carrying a state prison sentence of 2, 3, or 4 years.³ The middle term of 3 years is presumptive under current California sentencing law.

What Prosecutors Must Prove

California’s jury instructions lay out exactly what the prosecution needs to establish for a conviction. Under CALCRIM No. 580, there are two primary theories, plus a third theory under CALCRIM No. 581 involving a legal duty.^{4 5}

Theory 1: Unlawful Act Not Amounting to a Felony

The defendant committed a misdemeanor or infraction. The prosecution must identify a specific unlawful act, such as a traffic infraction, a misdemeanor weapons violation, or another non-felony offense. If the underlying act was not actually illegal, this entire theory collapses.

The defendant committed that act with criminal negligence. This is the most heavily contested element. Criminal negligence is far more than ordinary carelessness. The prosecution must show the defendant acted in a way that created a high risk of death or great bodily harm, and that a reasonable person would have recognized that risk.⁶

The defendant’s act caused the death of another person. Causation requires proof that the defendant’s conduct was a “substantial factor” in bringing about the death, not merely a minor or remote contributing cause.⁷

Theory 2: Lawful Act Committed With Criminal Negligence

The defendant was engaged in lawful conduct. Under this theory, the defendant was not committing any crime. They were doing something perfectly legal, like cleaning a firearm, operating machinery, or supervising children.

The defendant acted with criminal negligence while performing that lawful act. Even lawful activities become criminal when performed with a reckless disregard for human life that goes well beyond simple carelessness.⁸

The defendant’s negligent conduct caused the death. The same substantial-factor causation standard applies.

Theory 3: Failure to Perform a Legal Duty (CALCRIM 581)

The defendant had a legal duty to the person who died. This theory applies in specific relationships: parents to children, caregivers to patients, employers to employees in certain contexts.⁹

The defendant failed to perform that duty with criminal negligence. A parent who fails to seek medical attention for a seriously ill child, or a caregiver who neglects a dependent adult, may face charges under this theory.¹⁰

That failure caused the death. Again, the prosecution must prove the failure was a substantial factor, not just a contributing circumstance.

The Criminal Negligence Standard

If there is one legal concept that determines the outcome of most involuntary manslaughter cases, it is the distinction between ordinary negligence and criminal negligence. This is where cases are won and lost, and it deserves careful attention.

Ordinary negligence is the failure to use reasonable care. It is the standard in civil lawsuits, personal injury claims, and medical malpractice cases. Everyone makes mistakes that could be called “ordinarily negligent” at some point.

Criminal negligence is something qualitatively different. Under California law, a person acts with criminal negligence when they act in a reckless way that creates a high risk of death or great bodily harm, and a reasonable person would have known that acting in that way would create such a risk.¹¹

The gap between these two standards is enormous, and it is where defense attorneys do their most important work. Consider a few examples:

A homeowner who stores a loaded firearm in an unlocked drawer is arguably negligent. But a homeowner who hands a loaded firearm to someone who has never handled a gun, in a dark room, while intoxicated, is acting with criminal negligence. The question is always whether the conduct created a high risk that a reasonable person would have recognized.

In practice, prosecutors often try to blur this line, presenting ordinary carelessness as though it meets the criminal standard. An experienced defense team knows how to hold the prosecution to the higher threshold and make the jury understand the difference.

Penalties and Sentencing

Sentence Enhancements

Certain circumstances can significantly increase the prison exposure beyond the base term:

The firearm enhancement under PC 12022.5 is particularly significant because many involuntary manslaughter cases involve accidental shootings.¹² An allegation that adds up to 10 years can transform a case with a 4-year maximum into one carrying 14 years.

Strike Status

Involuntary manslaughter is generally not classified as a serious felony under Penal Code section 1192.7, subdivision (c), or a violent felony under Penal Code section 667.5, subdivision (c).^{13 14} This means it is typically not a strike offense under California’s Three Strikes law.

This distinction carries real strategic weight. Voluntary manslaughter (PC 192(a)) is a strike. Murder is a strike. Involuntary manslaughter is not. When our defense team negotiates charge reductions in homicide cases, the difference between a strike and a non-strike conviction can shape the rest of a client’s life.

Defense Strategies

Every involuntary manslaughter case has a unique set of facts, but several defense approaches have proven effective across the types of cases we see in the Bay Area.

Challenging the Criminal Negligence Threshold

The prosecution’s burden is to prove conduct that goes far beyond ordinary carelessness. In many cases, the defendant’s behavior, while perhaps unwise, did not create the kind of high risk of death that a reasonable person would have recognized. This is especially true in workplace accident cases, recreational activity injuries, and situations involving equipment failure. If the conduct was merely negligent in the civil sense, it does not meet the criminal standard.

Example: A property owner fails to repair a railing that eventually gives way, causing a fatal fall. Negligent? Possibly. But did the owner know or should they have known the railing created a high risk of death? That is a much harder question for prosecutors to answer.

Breaking the Chain of Causation

Even if the prosecution proves criminal negligence, they must also prove the defendant’s conduct was a substantial factor in causing the death.¹⁵ If an independent intervening cause contributed to the death (medical error during treatment, the victim’s own unforeseeable actions, a pre-existing medical condition), the causal chain may be broken.

Example: A person is injured due to the defendant’s conduct but dies days later from a hospital-acquired infection unrelated to the original injury. The defense can argue the infection, not the defendant’s act, was the actual cause of death.

The Accident Defense

Under CALCRIM No. 3404, a person is not guilty of a crime if they acted without the intent required for that crime and their conduct was accidental.¹⁶ This instruction is powerful in involuntary manslaughter cases because the charge already involves no intent to kill. If the defendant was engaged in lawful conduct, exercising ordinary care, and the death was a genuine accident, there is no crime.

This defense is particularly relevant in accidental shooting cases, recreational accidents, and situations where mechanical or equipment failure contributed to the outcome.

Self-Defense and Defense of Others

If the defendant was acting in lawful self-defense or defense of another person, a resulting death may be legally justified.¹⁷ Even where the force used was arguably excessive (imperfect self-defense), this can reduce a murder charge down to manslaughter and potentially support acquittal on involuntary manslaughter charges as well.

Challenging the Underlying Unlawful Act

Under Theory 1, the prosecution must prove the defendant was committing a specific misdemeanor or infraction at the time of the death. If the defense can show the underlying act was not actually unlawful, the theory fails entirely. This is a technical defense, but it can be decisive. For instance, if the prosecution alleges the defendant was violating a local ordinance that turns out not to apply to the defendant’s situation, the predicate offense disappears.

Suppression of Illegally Obtained Evidence

Statements taken without proper Miranda warnings, evidence obtained through warrantless searches, or forensic evidence collected in violation of the Fourth Amendment can all be challenged through suppression motions under Penal Code section 1538.5.¹⁸ In homicide cases, where the prosecution often relies heavily on the defendant’s own statements to establish the negligence element, suppressing those statements can fundamentally change the case.

How Involuntary Manslaughter Compares to Other Homicide Charges

Understanding where involuntary manslaughter sits within California’s homicide framework helps clarify both the stakes and the defense opportunities.

The absence of malice and intent is what separates involuntary manslaughter from every charge above it. This is also why involuntary manslaughter is frequently the target in plea negotiations when the prosecution’s evidence of intent or malice is weak. A skilled defense team can often negotiate a murder charge down to involuntary manslaughter, dramatically reducing both the sentence and the long-term consequences.

Collateral Consequences Beyond Prison

A felony involuntary manslaughter conviction reaches into nearly every area of a person’s life, often long after any prison sentence is served.

Employment and Professional Licensing

A felony conviction involving a death will appear on background checks and can disqualify individuals from positions in healthcare, education, law enforcement, finance, and many other regulated fields. Professionals holding licenses from state boards (medical, nursing, law, real estate, teaching) face disciplinary proceedings that can result in suspension or revocation. For working professionals, this consequence often matters as much as the sentence itself.

Immigration Consequences

Involuntary manslaughter may be classified as a crime involving moral turpitude or, in some circumstances, an aggravated felony under federal immigration law. For non-citizens, a conviction can trigger deportation proceedings, denial of naturalization, or bars to re-entry. Anyone facing these charges who is not a U.S. citizen should ensure their defense attorney understands the immigration implications from day one.

Firearm Rights

A felony conviction results in a lifetime prohibition on possessing firearms under Penal Code section 29800.¹⁹ This prohibition applies regardless of whether the offense involved a firearm.

Post-Conviction Relief Options

California law does provide paths forward after a conviction. Depending on the circumstances, options may include expungement under Penal Code section 1203.4, a certificate of rehabilitation, or early termination of probation. These remedies do not erase the conviction entirely, but they can help restore employment eligibility and demonstrate rehabilitation to licensing boards.

Where Your Case Will Be Heard in the Bay Area

Felony involuntary manslaughter cases in Alameda County are typically filed and heard at the Rene C. Davidson Courthouse at 1225 Fallon Street in Oakland, which serves as the primary felony courthouse for the county. Cases originating in southern Alameda County may be handled at the Hayward Hall of Justice, while those from the Fremont, Newark, and Union City areas may proceed through the Fremont Hall of Justice. Our Oakland headquarters is located minutes from the Rene C. Davidson Courthouse, which allows our team to maintain a consistent presence in the court where most of these cases are resolved.

Why Our Team Fights for Involuntary Manslaughter Defendants

Involuntary manslaughter cases require a defense team that understands both the legal complexity of homicide law and the human reality of what our clients are going through. Many of the people we represent in these cases are professionals, parents, and community members who never imagined facing a felony charge. They are dealing with grief over a death they did not intend to cause, on top of the fear and uncertainty of criminal prosecution.

The Nieves Law Firm Criminal Defense Attorneys brings the resources of one of the largest criminal defense teams in the Bay Area to every case. We investigate the facts independently, retain expert witnesses when needed, and challenge every element the prosecution must prove. Whether the strongest path forward is a motion to dismiss, a negotiated resolution, or a trial, our team prepares for each possibility from day one.

If you are facing involuntary manslaughter charges, do not wait to get experienced defense counsel involved. Contact The Nieves Law Firm Criminal Defense Attorneys for a complimentary consultation and let us start building your defense.

Talk to our defense team now

Involuntary Manslaughter Quick Reference