Criminal Law: Actus Reus, Mens Rea, and Homicide

The guilty act — a voluntary physical act (or unlawful omission where there is a legal duty).

The guilty mind — the mental state required for the offense (purpose, knowledge, recklessness, negligence, or strict liability).

Purposely → knowingly → recklessly → negligently.

An offense that does not require proof of mens rea as to one or more elements (e.g., many regulatory/public-welfare offenses).

Unlawful killing of another human being with malice aforethought.

Intent to kill; intent to cause serious bodily harm; depraved-heart (extreme recklessness); felony murder.

An intentional killing mitigated by adequate provocation / heat of passion (or imperfect self-defense in some jurisdictions).

An unintentional killing from criminal negligence or during an unlawful act not amounting to felony murder.

A killing occurring during the commission (or attempted commission) of an inherently dangerous felony may be murder even without intent to kill.

The requirement that mens rea and actus reus exist at the same time for liability.

When there is a legal duty to act (statute, contract, special relationship, voluntary assumption of care, creation of the peril) and the defendant can act.

When the defendant intends to harm one person but harms another, the intent transfers to the actual victim for the completed crime.