Canadian Criminal Law/Proof of Elements
In a Criminal trial, the crown will present evidence that will tend to establish the offence charged. Each offence in the Criminal Code is broken down into "elements" that comprise the offence. Each element must be proven beyond a reasonable doubt before a judge can consider making a verdict of guilt.
The elements of each offence are unique for each offence. For a list of elements of major offences, see Canadian Criminal Law/Offences. Common with all criminal offences in Canada are the basic requirements of an action or omission (known as the "actus reus") and a criminal intent (known as the "mens rea"). What constitutes a actus reus and mens rea depends on the offence itself. For example, a drug possession charge requires proving mens rea by establishing that the accused had knowledge of the presence of the substance on their person. An assault, however, requires proving a mens rea by establishing intended the application of force.
There are more static elements that need to be proven, such as the identity of the accused as the person subject to the offence, jurisdiction of the court over the person accused, and the timing of the offence. Identity can sometimes be a non-trivial issue where the accused was not caught in the act. Courts are very wary of wrongful convictions based on identity. The jurisdiction and time elements simply establish that the court is able to adjudicate the matter. Judges cannot concern themselves of offences outside of the province or offences without any specific time period.
Where defences are concerned, the Crown has no obligation to disprove them unless the evidence provides an "air of reality" to the availability of a defence.