Wisconsin Statutes & Annotations
Chapter 940 - Crimes against life and bodily security.
940.01 - First-degree intentional homicide.

940.01 First-degree intentional homicide.
(1) Offenses.
(a) Except as provided in sub. (2), whoever causes the death of another human being with intent to kill that person or another is guilty of a Class A felony.
(b) Except as provided in sub. (2), whoever causes the death of an unborn child with intent to kill that unborn child, kill the woman who is pregnant with that unborn child or kill another is guilty of a Class A felony.
(2) Mitigating circumstances. The following are affirmative defenses to prosecution under this section which mitigate the offense to 2nd-degree intentional homicide under s. 940.05:
(a) Adequate provocation. Death was caused under the influence of adequate provocation as defined in s. 939.44.
(b) Unnecessary defensive force. Death was caused because the actor believed he or she or another was in imminent danger of death or great bodily harm and that the force used was necessary to defend the endangered person, if either belief was unreasonable.
(c) Prevention of felony. Death was caused because the actor believed that the force used was necessary in the exercise of the privilege to prevent or terminate the commission of a felony, if that belief was unreasonable.
(d) Coercion; necessity. Death was caused in the exercise of a privilege under s. 939.45 (1).
(3) Burden of proof. When the existence of an affirmative defense under sub. (2) has been placed in issue by the trial evidence, the state must prove beyond a reasonable doubt that the facts constituting the defense did not exist in order to sustain a finding of guilt under sub. (1).
History: 1987 a. 399; 1997 a. 295.
Judicial Council Note, 1988: First-degree intentional homicide is analogous to the prior offense of first-degree murder. Sub. (2) formerly contained a narrower definition of “intent to kill" than the general definition of criminal intent. That narrower definition has been eliminated in the interest of uniformity. Section 939.23 now defines the intent referred to.
The affirmative defenses specified in sub. (2) were formerly treated in s. 940.05. This caused confusion because they seemed to be elements of manslaughter rather than defenses to first-degree murder. Sub. (2) specifies only those affirmative defenses which mitigate an intentional homicide from first to 2nd degree. Other affirmative defenses are a defense to 2nd-degree intentional homicide also, such as self-defense, i.e., when both beliefs specified in sub. (2) (b) are reasonable. Section 939.48.
The prosecution is required to prove only that the defendant's acts were a substantial factor in the victim's death; not the sole cause. State v. Block, 170 Wis. 2d 676, 489 N.W.2d 715 (Ct. App. 1992).
The trial court must apply an objective reasonable view of the evidence test to determine whether under sub. (3) a mitigating affirmative defense “has been placed in issue" before submitting the issue to the jury. Shawn B.N. v. State, 173 Wis. 2d 343, 497 N.W.2d 141 (Ct. App. 1992).
Imperfect self-defense contains an initial threshold element requiring a reasonable belief that the defendant was terminating an unlawful interference with the defendant's person. State v. Camacho, 176 Wis. 2d 860, 501 N.W.2d 380 (1993).
Sub. (1) (a) cannot be applied against a mother for actions taken against a fetus while pregnant as the applicable definition of human being under s. 939.22 (16) is limited to one who is born alive. Sub. (1) (b) does not apply because s. 939.75 (2) (b) excludes from its application actions by a pregnant woman. State v. Deborah J.Z., 228 Wis. 2d 468, 596 N.W.2d 490 (Ct. App. 1999), 96-2797.
A defendant seeking a jury instruction on perfect self-defense to a charge of first-degree intentional homicide must satisfy an objective threshold showing that the defendant reasonably believed that the defendant was preventing or terminating an unlawful interference with the defendant's person and reasonably believed that the force used was necessary to prevent imminent death or great bodily harm. A defendant seeking a jury instruction on unnecessary defensive force under sub. (2) (b) to a charge of first-degree intentional homicide is not required to satisfy the objective threshold. State v. Head, 2002 WI 99, 255 Wis. 2d 194, 648 N.W.2d 413, 99-3071.
A defendant who claims self-defense to a charge of first-degree intentional homicide may use evidence of a victim's violent character and past acts of violence to show a satisfactory factual basis that the defendant actually believed the defendant was in imminent danger of death or great bodily harm and actually believed that the force used was necessary to defend himself or herself, even if both beliefs were unreasonable. State v. Head, 2002 WI 99, 255 Wis. 2d 194, 648 N.W.2d 413, 99-3071.
A privilege for excusable homicide by accident or misfortune is incorporated in s. 939.45 (6). Accident is a defense that negatives intent. If a person kills another by accident, the killing could not have been intentional. Accident must be disproved beyond a reasonable doubt when a defendant raises it as a defense. When the state proves intent to kill beyond a reasonable doubt, it necessarily disproves accident. State v. Watkins, 2002 WI 101, 255 Wis. 2d 265, 647 N.W.2d 244, 00-0064.
A defendant may demonstrate that the defendant was acting lawfully, a necessary element of an accident defense, by showing that the defendant was acting in lawful self-defense. Although intentionally pointing a firearm at another constitutes a violation of s. 941.20, under s. 939.48 (1) a person is privileged to point a gun at another person in self-defense if the person reasonably believes that the threat of force is necessary to prevent or terminate what the person reasonably believes to be an unlawful interference. State v. Watkins, 2002 WI 101, 255 Wis. 2d 265, 647 N.W.2d 244, 00-0064.
The common law “year-and-a-day rule" that no homicide is committed unless the victim dies within a year and a day after the injury is inflicted is abrogated, with prospective application only. State v. Picotte, 2003 WI 42, 261 Wis. 2d 249, 661 N.W.2d 381, 01-3063.
An actor causes death if the actor's conduct is a substantial factor in bringing about that result. A substantial factor need not be the sole cause of death for one to be held legally culpable. Whether an intervening act was negligent, intentional, or legally wrongful is irrelevant. The state must still prove beyond a reasonable doubt that the defendant's acts were a substantial factor in producing the death. State v. Below, 2011 WI App 64, 333 Wis. 2d 690, 799 N.W.2d 95, 10-0798.
Under the facts of this case, the court did not err in denying an intervening cause instruction. Even if the defendant could have established that the termination of the victim's life support was “wrongful" under Wisconsin law, that wrongful act would not break the chain of causation between the defendant's actions and victim's subsequent death. State v. Below, 2011 WI App 64, 333 Wis. 2d 690, 799 N.W.2d 95, 10-0798.
Barring psychiatric or psychological opinion testimony on the defendant's capacity to form an intent to kill is constitutional. Haas v. Abrahamson, 910 F.2d 384 (1990).
The Importance of Clarity in the Law of Homicide: The Wisconsin Revision. Dickey, Schultz, & Fullin. 1989 WLR 1323.
State v. Camacho: The Judicial Creation of an Objective Element to Wisconsin's Law of Imperfect Self-Defense Homicide. Lieser. 1995 WLR 741.

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