Admissibility of unlawfully obtained DNA evidence

44.97 DNA evidence is a form of expert opinion evidence. Opinion evidence is admissible if it is wholly or substantially based on a person’s specialised knowledge, which in turn is based on the witness’ training, study or experience.^[89] DNA evidence that is relevant to a fact in issue is admissible in criminal proceedings unless it is barred under an exclusionary rule, or by judicial discretion.^[90]

Crimes Act provisions

44.98 Part 1D of the Crimes Act provides that evidence obtained from a forensic procedure is inadmissible if there has been a breach of, or failure to comply with, the provisions of Part 1D in relation to the forensic procedure or in relation to recording or use of information on the DNA database system. However, the court has a discretion to admit the evidence if it is satisfied on the balance of probabilities of matters that justify its admission in spite of the non-compliance; or if the person who is the subject of the forensic evidence does not object to its admission.^[91] Section 23XX(5) provides a list of matters that the court may consider in making this decision. The probative value of the evidence will not itself justify the admission of the evidence.^[92] Evidence obtained as a result of a forensic procedure is not admissible in proceedings against a person if it is required to be destroyed under Part 1D.^[93]

Evidence law

44.99 The Crimes Act provisions do not apply to DNA evidence obtained outside the framework of Part 1D—for example, a crime scene sample, or an informally obtained sample.^[94] The admissibility of such evidence would be subject to the rules of evidence applying in the relevant jurisdiction.

44.100 Under the Evidence Act, the court must exclude evidence led by the prosecution if its probative value is outweighed by the danger of unfair prejudice to the defendant.^[95] The court must exclude evidence that has been improperly or unlawfully obtained unless the desirability of admitting the evidence outweighs the undesirability of admitting evidence obtained in this way.^[96] Finally, the court has a discretion to exclude evidence where it considers the probative value is substantially outweighed by the danger that the evidence might be unfairly prejudicial, misleading or confusing, or might result in an undue waste of time.^[97]

Admissibility of DNA evidence

44.101 Exclusionary rules of evidence are a primary means of deterring the illegal or improper collection, use or retention of DNA evidence. The Crimes Act provides the judge with a balancing test when determining whether to admit DNA evidence obtained in breach of the provisions of Part 1D. A similar approach is taken in the Evidence Act, in relation to evidence that is obtained improperly or illegally.^[98]

44.102 The Inquiry has heard concerns that due to the highly probative nature of DNA evidence, judges might tend to exercise their discretion in favour of admission rather than properly balancing each of the relevant interests, including the privacy of the accused. This would undermine the value of the protection intended by MCCOC in formulating this provision.^[99]

44.103 Chapter 41 discusses concerns arising from the informal collection of genetic samples by police investigators. In that chapter, the Inquiry noted that legislative provisions regarding the inadmissibility of improperly or unlawfully obtained evidence might not provide sufficient safeguard against these practices. For example, police investigators could collect a suspect’s sample informally. If the person is excluded from suspicion, or if the person is implicated but a formal sample is subsequently taken pursuant to the Crimes Act provisions, the admissibility of the covertly obtained sample would not arise as an issue in proceedings.

44.104 Rather than amending the legislative provisions regarding admissibility of DNA evidence, the Inquiry considers it would be more useful to protect against the informal or unlawful collection of the genetic information in the first place. Therefore, Recommendation 41–13 provides that theCommonwealth should amend the Crimes Act to provide that, with the exception of crime scene samples, law enforcement officers may lawfully collect a genetic sample for law enforcement purposes only from (a) the individual concerned, pursuant to Part 1D of the Crimes Act; or (b) a stored sample, with the consent of the person sampled or a person authorised to consent on his or her behalf, or pursuant to a court order.