Wisconsin First-Degree Murder

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First-degree murder is the most serious of homicide offenses in Wisconsin. It's punished by life imprisonment only, as Wisconsin abolished the death penalty in 1853. Although, after the Jeffrey Dahmer case there was a brief movement to reinstate the death penalty.

Essentially, first degree murder is the intentional killing of another. However, if a person can show one of the four statutory defenses apply, then the charge is lowered to a charge of second-degree intentional homicide.

Felony Murder

In some states, felony murder or causing the death of another while committing or attempting to commit a serious violent crime (battery, sexual assault, false imprisonment, kidnapping, arson, burglary, carjacking, and robbery) is a part of first-degree murder. In other states, it's considered second-degree murder. In Wisconsin, felony murder has its own statute, section 940.03, and at most the punishment is 15 years more in prison than the maximum term of imprisonment for the underlying crime committed or attempted.

Wisconsin First Degree Murder Laws: Statute

Details on Wisconsin's first degree murder law are outlined below.

Code Sections

Wisconsin Statutes Section 940.01: First-Degree Intentional Homicide

What Is Prohibited?

First degree murder in Wisconsin is to cause the death of another human or an unborn child with the intent to kill that person, or for a fetus an intent to kill the pregnant woman or unborn child. Note that the defendant doesn't need to be the only cause of the person or unborn child's death, only a substantial factor in the victim's death.


First-Degree Intentional Homicide is a Class A felony which can be sentenced to only life imprisonment.

If the killing is lowered to Second-Degree Intentional Homicide for any of the reasons listed in Defenses below, then it's a Class B felony with a sentencing maximum of 60 years in prison. For many people, long prison sentences are the equivalent of life in prison.


This law provides for four mitigating circumstances, which are affirmative defenses that turn the offense to the lower level second-degree intentional homicide. If a defendant asserts any of these affirmative defenses, the prosecutor must prove beyond a reasonable doubt that the facts for the defense(s) raised didn't exist in order to get a guilty verdict. The four mitigating circumstances are:

  • Adequate Provocation - The death was cause under the influence of a provocation that causes him or her to lose self-control and would do so in an ordinary person, this is home Wisconsin law addresses "heat of passion" manslaughter.
  • Unnecessary Defensive Force - When the death was caused as the defendant believing he or she or another person was in imminent danger of death or serious physical injury and that the force he or she used was necessary to defend whoever was endangered, but the judge or jury thought either the belief of danger or the force being necessary wasn't reasonable. This is the "imperfect" self-defense claim. If self-defense is truly reasonable, then it's a "complete" defense and the person is found not guilty.
  • Prevention of a Felony - If the death was caused because the defendant believed that the force used was necessary to prevent or stop a felony, but that belief was unreasonable.
  • Coercion or Necessity - The death was caused by coercion (defendant is threatened by a person so that he or she feels the killing is the only way to prevent imminent death or serious physical injury to himself or herself or another, not just, for example, the safest course rather than only course or was commanded by a spouse) or necessity (the defendant reasonably believed that he or she had to act due to natural physical forces to prevent an imminent disaster, death, or serious physical harm to himself or herself or another, not the use of heroin in prison despite addiction as it's not a natural force)

Additional complete defenses to a first-degree murder charge may be relevant, such as innocence or insanity. The death being an accident is a defense that negates the intent to kill required by this law. In that case, a reckless or negligent homicide charge may apply; see the Wisconsin Involuntary Manslaughter article for more information.

Note: State laws change regularly -- it's important to verify the laws you are researching.

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Wisconsin First Degree Murder Laws: Related Resources

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