8.4.5: Inference of Intent

The deadly weapon doctrine creates an inference of murder intent when the defendant uses a deadly weapon (People v. Carines, 2011). A judge may instruct the jury that they can infer the defendant intended the natural and probable consequences of the criminal act, which are death when a deadly weapon is utilized. This basically alleviates the burden of having to prove criminal intent for murder. A deadly weapon is any instrumentality that can kill when used in a manner calculated to cause death or serious bodily injury (Acers v. United States, 2010).

Under California Law, the definition of “deadly weapon” includes firearms and “any object, instrument, or weapon that is inherently deadly or one that is used in such a way that it is capable of causing and likely to cause death or great bodily injury (CA PC 245, 2024).”

 

Considerations include:

• Lethality of the object: The object has the actual or apparent ability to inflict significant harm or death;
• Intended use of the object: The object’s inherent design or modification for use as a weapon; and
• Circumstances surrounding the object’s use: Whether the defendant wielded the object as a weapon in a threatening manner and the proximity of the object to the victim.

Some examples of deadly weapons are knives, guns, broken bottles, or even bare hands if there is a discrepancy in the size of the attacker and the victim. Aside from creating an inference of intent for murder, use of a deadly weapon may also enhance a sentence for certain crimes.

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