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  • Writer's pictureJarrod Carter

Propensity and Relationship Evidence

In the realm of Western Australian criminal law, propensity evidence and relationship evidence bear significant weight. Propensity evidence constitutes proof that an individual has a predisposition to perform certain actions or behave in specific manners. Meanwhile, relationship evidence involves evidence of the connection that an individual has had or currently has with another person or group of people. The admissibility of these evidentiary forms is subjected to strict rules, which we will explore in this article.

At a cursory glance, it seems like these forms of evidence should not be admissible. How can your previous actions provide evidence that you were involved in some specific event taking place in the future? It would imply that having a criminal record can be used against you prejudicially in a later case. Further, how can your association with a particular person provide reliable evidence of guilt?

To gain a deeper understanding of the topic, we must first examine what is meant by propensity and relationship evidence. Propensity evidence is classified under Section 31A of the Evidence Act 1906, which characterizes it as either evidence of the conduct of the accused that is akin to similar fact evidence, or evidence of the character or reputation of the accused person. On the other hand, relationship evidence is defined under the same section as evidence of the attitude or behavior of the accused person towards a particular person or group of people over a duration of time.

In the event that these types of evidence are presented, the court must assess whether they are admissible under Section 31A(2) of the Act. The admissibility of propensity and relationship evidence is based on whether the court considers the evidence relevant, has significant probative value, and whether its probative value outweighs any unfair prejudice that it may have on the accused person.

Probative Value

The question of “probative value" refers to any evidence that is relevant and useful in proving a fact or issue in a legal case. This evidence can include witness testimony, physical evidence, documents, and other forms of evidence that help to establish the truth of a matter. To be admissible in court, evidence must be not only relevant, but also have probative value, meaning that it tends to make the existence of a fact more or less likely. The weight of probative value assigned to a particular piece of evidence depends on factors such as its reliability, credibility, and consistency with other evidence presented in the case.

Unfair Prejudice

In legal terms, "unfair prejudice" refers to a situation where the introduction of certain evidence or argument in a trial or hearing may unduly influence the decision maker against one party, and the probative value of that evidence or argument is outweighed by its potential to create an unfair bias or prejudice against that party. Unfair prejudice is often used as a reason to exclude evidence that may be technically relevant, but could be highly inflammatory or emotionally charged, and may unfairly influence the jury or judge. In determining whether evidence should be excluded on the basis of unfair prejudice, the court will consider factors such as the strength of the evidence, the extent of its prejudicial effect, and whether there are any alternative means to prove the same point without creating an unfair prejudice.

Relationship evidence may also be admissible if it has significant probative value in relation to a fact in issue, or if it is necessary to explain the relationship between the accused and the victim or witness.

Examples of Propensity and Relationship Evidence

Examples of propensity evidence include evidence of previous convictions or charges for similar offences, evidence of previous uncharged conduct, or evidence of statements made by the accused which suggest a tendency to engage in particular conduct.

Examples of relationship evidence may include evidence of prior threatening or violent behavior towards a particular person, evidence of prior sexual relations with the victim, or evidence of a long-standing animosity between the accused and the victim.

In the legal context, the admissibility of evidence is crucial to ensuring a fair and just trial. In determining whether evidence is admissible, the court must first establish whether the evidence is propensity or relationship evidence and whether it is relevant to a fact in issue. If the evidence is relevant to a fact in issue, the court must then assess whether it has significant probative value.

When it comes to propensity or relationship evidence, the presiding judge or magistrate must balance the probative strength of the evidence with the degree of risk of an unfair trial if the evidence is admitted. This balancing exercise must be done from the perspective of a fair-minded person, which has been interpreted to mean a member of the general public who is not a lawyer.

It's worth noting that with Section 31A of the Western Australia Evidence Act 1906, the court has recognized the importance of providing the jury with a full evidentiary familial picture. This means that evidence with an underlying unity or pattern to all of the evidence may be admissible, even if it could be considered propensity or relationship evidence. Ultimately, the decision to admit or exclude evidence is up to the discretion of the judge or magistrate, and must be made in accordance with the principles of fairness and justice.

In some cases, the state may seek to admit evidence of the accused's conduct with respect to some counts on the indictment as propensity or relationship evidence with respect to other counts. This may include previously charged or uncharged acts.

Claremont Serial Killer Case

In The State of Western Australia v Edwards [2019] WASC 87, the State filed an application seeking the admissibility of propensity evidence in the Claremont Serial Killer case. The state aimed to lead evidence with respect to the Karrakatta offences and the Huntingdale offences. The state argued that the accused had a tendency to prowl an area of familiarity at night-time in a distinctive manner to create or seize an opportunity to commit an offence with a sexual motive.

The Karrakata Incident

Edwards pleaded guilty to the Karrakata offences which included sexual assault. A young woman, who was 17, provided multiple lengthy statements regarding her abduction from Rowe Park on February 12, 1995, which were read out in the West Australian Supreme Court. She said, 'I thought at the end of it all that he was going to kill me,' although he did not directly threaten her. The girl had been out with friends but she decided to walk a couple of hundred meters to a friend's home. As she explained in her statement, 'I usually leave with someone but I just wanted to go.' On the way, Edwards grabbed her from behind, pushed her to the ground, straddled her, and forcibly inserted a thick cloth, resembling a sock, deep into her mouth. Bradley tied her hands tightly, carried her to his van, tied her ankles, and covered her head with a cotton bag. He then drove her for approximately 30 minutes. When the vehicle eventually stopped, Bradley pulled her out, and carried and dragged through Karrakatta Cemetery before twice sexually assaulting her.

The Huntingdale Incident

Edwards also pleaded guilty to a deprivation of liberty charge during a break-in at a residence in Huntingdale, located in Perth's southeast region, in 1988. During the break-in, Edwards entered the victim's room while she was asleep and placed his hands over her mouth and head, preventing her from moving or making noise. The victim initially thought it could be her boyfriend or brothers playing a prank, but soon realized it was was a stranger. When Edwards attempted to cover the victim's mouth with a piece of cloth, she managed to say "I love you," causing Edwards to stop what he was doing. The victim then reached up to stroke his face, still thinking it could be her boyfriend, but realized he had stubble instead of a clean-shaven face. She dug her fingernail into Edwards' skin and he lifted himself off of her. The victim saw a tall man standing in the doorway wearing a woman's nightie before he fled. She shouted for her father to alert him of the break-in. The victim testified in court and Edwards pleaded guilty to the charges against him.

Admission of Propensity Evidence

The State argued that the propensity evidence established a high degree of probative value due to the common features found in the Huntingdale Offences and the Karrakatta offences. The State further submitted that the propensity evidence demonstrates an underlying unity in the offending, which goes to the fact in issue, specifically identity.

The Judge agreed that the evidence was admissible with respect to the Huntingdale offences, as all incidents occurred in the same geological area, were close in time, and the wearing or possession of a kimono was found to connect these incidents. However, the use of the phrase ‘prowl’, ‘distinctive manner’, and ‘sexual motive’ were found to be encompassing a wide range of conduct and therefore did not meet the significant probative value test. As a result, this evidence was not admissible with respect to the Karrakatta Offence or the Claremont Murder Offence.

The Judge found that the evidence of the Huntingdale Offences was admissible with respect to each and every other count on the indictment. When considering any prejudice against the accused, the judge expressed that any such risk is less likely in the case of a trial by Judge alone, as the Judge had the capability to disregard evidence where necessary. Overall, the judge exercised caution in the admissibility of propensity evidence and relationship evidence to ensure a fair trial for the accused.


Propensity and relationship evidence can be highly unjust in legal proceedings because it unfairly creates a bias against the accused or witness based on factors that are unrelated to the specific facts of the case.

Propensity evidence, which suggests that a person is more likely to have committed a crime based on their past behavior or character, is particularly problematic because it assumes that people cannot change or learn from their mistakes. This type of evidence also overlooks the possibility that the person may have been wrongly accused or may have been the victim of an unjust legal system in the past.

Similarly, relationship evidence, which suggests that a person's association with a particular individual or group makes them more likely to be guilty or less credible, is also problematic. This type of evidence ignores the fact that people may have diverse relationships with others for various reasons, and that such relationships do not necessarily make them guilty or untrustworthy.

The use of propensity and relationship evidence can also create a false narrative around the accused or witness, which can be difficult to overcome even if the evidence is ultimately excluded or disproven. This can lead to a situation where the accused or witness is unfairly stigmatized or subject to discrimination, even if they are ultimately found innocent or truthful.

Judges can ensure that propensity and relationship evidence is not unjustly admitted into evidence by applying a rigorous and fair standard of admissibility. This standard should balance the probative value of the evidence with its potential to create unfair prejudice against the accused or witness.

One way to achieve this balance is to require that the evidence meets a high standard of relevance and materiality. The evidence must be directly related to the specific facts of the case and must be necessary to prove a particular element of the crime or issue in question. Additionally, judges can require that the evidence be supported by sufficient proof to establish its reliability and credibility. This can include requiring that the evidence be based on clear and convincing evidence, rather than mere speculation or hearsay.

Another way judges can ensure that propensity and relationship evidence is not unjustly admitted is by considering alternative sources of evidence that may be less prejudicial. For example, if the evidence can be proven through other means, such as eyewitness testimony or physical evidence, then the propensity or relationship evidence may be unnecessary and unduly prejudicial. Finally, judges can provide appropriate instructions to the jury on how to consider and weigh the propensity and relationship evidence, and can caution them against using such evidence to draw improper inferences or conclusions.

In summary, judges must ensure that propensity and relationship evidence is not unjustly admitted into evidence by applying a high standard of relevance and materiality, requiring sufficient proof of reliability and credibility, considering alternative sources of evidence, and providing appropriate instructions to the jury.

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