R v MJJ; R v CJN

This case concerned appeals against conviction and sentence brought by R v MJJ and R v CJN. The appeals involved the admissibility of evidence of discreditable conduct under the *Evidence Act 1929* (SA), specifically section 34P, and the sentencing discretion of the trial judge. The Court of Criminal Appeal of South Australia was required to determine whether the trial judge had erred in admitting certain evidence and whether the sentences imposed were appropriate.

The primary legal issues before the court were: (1) the correct interpretation and application of section 34P of the *Evidence Act 1929* (SA) concerning the admissibility of evidence of discreditable conduct, and whether the trial judge had correctly applied this provision; and (2) whether the sentences imposed on MJJ, including the head sentence and non-parole period, were within the proper exercise of the sentencing judge's discretion.

The court considered that section 34P of the *Evidence Act 1929* (SA) regulates the admissibility of discreditable conduct evidence, requiring that such evidence cannot be used to suggest a defendant is more likely to have committed an offence due to past discreditable conduct. While the Act modifies common law principles, the court found that common law authorities on the probative force of discreditable conduct evidence and the weighing of its probative value against prejudicial effect continue to inform the application of section 34P. The court noted that section 34P(2) allows for the admission of such evidence for a permissible use if its probative value substantially outweighs any prejudicial effect, and if it has strong probative value when used as circumstantial evidence of a propensity or disposition. Regarding sentencing, the court held that the sentence imposed on MJJ, while substantial, was within the sentencing judge's discretion, considering his criminal antecedents and the nature of the offending.

The appeals against conviction were dismissed. Leave to appeal against sentence was granted to MJJ, but that appeal was also dismissed.