Thursday, 3 January 2013

Law report - expert evidence on gang members

Cox v R (2011) Crim App 15/15A
Myers v R (2011) Crim App 17

The Appellants had been convicted of murder and using a firearm. In both cases the Prosecution had relied on "gang evidence", i.e. evidence of specialist police officers who were familiar with the gangs on the island.

The officers gave evidence that the Appellants were members of 42nd Street (Cox) and Parkside (Myers), which were rival gangs, and that their victims were members of the other gang. The officers gave evidence of a feud between the gangs and of the ongoing tit for tat retaliation between them, which they said was sufficient reason for the Appellants to kill rival gang members

The Appellants appealed on the grounds that the evidence was irrelevent, amounted to hearsay, that the police officers were not experts and so unable to give an expert opinion, and was inadmissible as it was putting evidence of general bad character before the court which could prejudice the jury.

It was HELD by Evans JA and Zacca JA that the evidence of the police officers was relevant as evidence of a motive is clearly relevant to whether somebody is guilty.

The police officers dealt with the gangs on a daily basis and so had sufficient expertise to give their expert opinion on how the gangs operated.

Although the gang evidence might show the bad character or tendency to violence of the accused, it was directly relevant to the offence and, without that evidence, the case put to the jury would appear incomprehensible or incomplete.

As long as the judge explains the source of the witness' expertise, it is acceptable to describe a police officer as an expert. However, "gang expert" is not a particularly helpful term, and it would be better to spell out that he is an expert on gang behaviour.
The Court of Appeal suggested that careful consideration in future cases should be given as to:
  • distinguishing factual evidence from opinion evidence;
  • what parts of factual evidence are based on hearsay;
  • establishing an officer's qualifications and experience;
  • using terms such as "experienced police officer" or "expert on gang behaviour" rather than "gang expert";
  • directing the jury as to the scope of the opinion evidence  and the basis for admitting it;
  • bearing in mind the potential prejudice to the defendent of the evidence before admitting it
The two judges dismissed the appeals

Auld JA also said that he would dismiss the appeals but dissented on the issue of the gang evidence. There was enough scientific and factual evidence to show that the defendants intended to kill their victims, without relying on the gang evidence. He said that at best the evidence shows a shared motive with other people, but does not provide evidence that the jury can rely on to be sure of the defendant's guilt.

 He also explained his unease with using gang evidence generally. Gang evidence is not a science, and so it is difficult for a trial judge to determine in what circumstances a purported expert is in fact an expert. If trial judges do not sufficiently scrutinise the issue of the value of the evidence and the prejudice to the defence, then there is a danger of drifting into a culture of prosecutors attempting to bolster borderline cases with gang evidence of limited value but which is highly prejudicial.
Such evidence should be admitted only when it has a clear probative effect or supporting the effect of other evidence, balanced against its prejudice to the defence.

It would be difficult for the defence to find its own experts to counter the prosecution's gang evidence and, given their relationship with the prosecution, police officers are unlikely to be perceived as impartial, which is normally expected of expert witnesses.

Comment - it appears that the issue of gang evidence will go onwards and upwards to the Privy Council for final determination.

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