Explain how 'actus reus' and 'mens rea' must concur to establish criminal liability, and provide an example where the lack of concurrence would negate culpability.

To establish criminal liability, the prosecution must generally prove two essential elements: 'actus reus' and 'mens rea'. 'Actus reus' refers to the guilty act, or the physical component of the crime. It is the act or omission that constitutes the illegal conduct. 'Mens rea' refers to the guilty mind, or the mental state of the defendant at the time of the act. It is the intent or knowledge that is required for the crime. For criminal liability to exist, the 'actus reus' and 'mens rea' must concur, meaning they must occur at the same time. The defendant must have the required mental state at the time they commit the guilty act. If the 'actus reus' and 'mens rea' do not concur, criminal liability may be negated. An example of where the lack of concurrence would negate culpability is as follows: Imagine a person intends to poison their spouse by putting poison in their coffee. However, before the spouse drinks the coffee, they accidentally trip and fall, hitting their head and dying instantly. In this scenario, the person had the 'mens rea' to commit murder (the intent to kill their spouse by poisoning them). However, the 'actus reus' of poisoning did not cause the death. The spouse died from an accidental fall, not from the poison. Therefore, because the 'actus reus' and 'mens rea' did not concur – the intent to kill did not cause the act that resulted in death – the person would not be guilty of murder. They might, however, be guilty of attempted murder, since they performed an act with the intent to kill, even though that act did not ultimately cause the death.