Police Officer Rules When Obtaining Evidence

Key Takeaways

  • There are very strict rules about what a police officer can and can’t do in order to obtain evidence.
  • If you feel police have unlawfully obtained certain evidence, you can argue for it’s exclusion as evidence during the “pre-trial”.
  • If a police officer wants to search you, your vehicle or your house, they must have a warrant, or suspect that a crime has been committed based on initial observations or something you have said to them.
  • If you are being charged, you can call Cridland & Hua’s 24 hour number here: +61 7 3211 3177
Need more information? Contact Brisbane’s leading criminal lawyers here:

    If the police obtain evidence unlawfully, can it still be used against a defendant?

    Police officers, just like everybody else, must abide by laws when they are doing their job. In Queensland, the conduct, powers and responsibilities of all police officers are regulated by a law known as the ‘Police Powers and Responsibilities Act’.  This is a very lengthy piece of law and some parts of it can be very complicated.  Given that the police have such extensive powers it is only appropriate that they be subjected to such strict laws.

    One particularly troublesome area of this law, which causes issues time and time again, deals with the manner in which police obtain evidence. There are very strict rules about what a police officer can and can’t do in order to obtain evidence and breaking these rules may lead to the exclusion of this evidence at a criminal trial, meaning that it can’t be used by the police against a defendant.  Before many matters proceed to trial to determine whether a defendant is guilty or not guilty, there will be a ‘pre-trial’ step which usually focuses on what evidence should and shouldn’t be allowed to be placed before a jury.  It is during this step that the defendant has the opportunity of arguing that the police shouldn’t be allowed to use certain evidence that they have obtained because the manner in which they obtained it was unlawful.

    Issues will commonly arise when dealing with police searches (for example, the search of a car that has been pulled over on the street by the police or the search of a house) or where the defendant has said certain things to the police that indicate guilt (for example, in an interview with the police). When dealing with searches, certain things must be satisfied before a police officer can search a person – for example, the police officer must suspect that an offence has been committed or about to be committed or that if an immediate search is not undertaken evidence might be destroyed.  When dealing with admissions made by the defendant, the police officer must inform a suspect of all of their rights, including the right to silence or a right to a lawyer.

    So if the police break the rules to obtain evidence, is it immediately inadmissible?

    The short answer is no. In Australia, the position is different to other parts of the word where any breaking of the law will mean that the evidence is automatically inadmissible, regardless of how minor the breaking of the law was or how important the evidence is against a suspect.  In Australia, even if the police break the law to obtain evidence, the court will ultimately have a discretion as to whether or not it should be ruled inadmissible.  The court will look at a number of factors, including:

    1. How serious the breach of the law was (including whether or not the breach of the law was deliberate or simply an oversight by a police officer)
    2. What other options were available to the police officer in order to have complied with the law
    3. How important the evidence is
    4. How serious the crime that a defendant has been charged with is

    The court will then perform a balancing exercise to decide whether or not the evidence should be allowed to be used by the police.

    Take for example the following hypothetical scenario. A police officer searches a storage shed without a warrant (unlawfully) and discover a very large quantity of drugs.  The police office had the time and opportunity to, before they searched the shed, obtain a warrant in order to search the shed lawfully but failed to do so.  It is discovered that the reason why the police officer didn’t obtain a search warrant was because they were a very junior officer who didn’t fully understand the law and that the breaking of the rules was therefore not deliberate on their part.  In a case such as this, given that the breaking of the law was not deliberate but the crime was very serious and would result in a very lengthy prison term, a judge is likely to rule that the evidence is admissible against the defendant at their trial.

    This is a very simplified example but in real life they are much more complicated. The police officers will be questioned by defence lawyers in very fine detail about what information they had at the time, what other options were available to them, what advice they took from their bosses and why they took the steps that they did in order to obtain the evidence.  And then there is the task of attempting to weigh this against the seriousness of the offence – difficult because it’s not always so easy to determine what exactly is or isn’t a serious offence and different judges will have different opinions.

    When charged with a criminal offence it is therefore very important to engage a good and experienced criminal lawyer because they will know whether or not the police have acted lawfully or unlawfully and, if possible, how to argue to have unlawfully obtained evidence excluded.

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