What is actus reas and why does it matter?

Actus reus for those who took Latin in High School means "guilty act". It refers to the physical or external component of a crime as opposed to the criminal mental state. It is the conduct itself, the wrongful act that is prohibited by law.

For criminal responsibility, the actus reus must generally be voluntary. When Huey Newton shot a police officer many years ago, his defense was that a bullet wound to his stomach caused such pain that his firing a gun was an involuntary action, a reflex and not a choice.

A crime requires an act (actus reus) and a wrongful intent (mens rea).

Key Forms of Actus Reus

In rare instances an omission (failure to act) can be a crime if there is a legal duty to act. A parent neglecting a child would be an example.

If a drug dealer sells drugs and a person using the drugs dies of an overdose is the selling of drugs an actus reus that qualifies the drug dealer for a murder charge? Or is the act of selling drugs too distant from the death so it does not qualify as an actus reus for murder?

This issue has been addressed in the federal courts in part by statute. Under federal law, 21 U.S.C. § 848(e)(1)(A) criminalizes intentional murder committed while engaged in drug trafficking offenses. The actus reus for this offense is "intentional killing, an injury that is distinct from and in addition to that addressed by the predicate crimes" (United States v. Aquart, 92 F.4th 77 (2024)

This can be a fact based inquiry. Administering drugs is more connected to a death than selling drugs.

In conclusion, actus reas is usually not an issue in criminal cases but when a consequence is not directly intended by the underlying act or when the perpetrator’s mental state is severely impaired, it can be an important issue.

Daniel Horowitz is a criminal defense specialist certified by the State Bar of California Board of Legal Specialization.  Call Daniel for an initial consultation at 925-283-1863