R v Deen
| Jurisdiction | England & Wales |
| Judgment Date | 21 December 1994 |
| Date | 21 December 1994 |
| Court | Court of Appeal (Criminal Division) |
Court of Appeal
Before Lord Taylor of Gosforth, Lord Chief Justice, Mr Justice Owen and Mr Justice Latham
Criminal evidence - DNA test - "prosecutor's fallacy" explained
The "prosecutor's fallacy" of confusing what was known as the DNA match probability with what was known as the likelihood ratio was explained by the Court of Appeal when explaining in outline the basic technicalities of the complex process of DNA (deoxyribonucleicacid) profile matching.
The court was giving reserved reasons for having allowed an appeal, quashed a conviction and ordered the retrial of a man convicted of three rapes who had been sentenced to 16 years imprisonment.
Mr Michael Mansfield, QC and Mr Robert Platts, assigned by the Registrar of Criminal Appeals, for the appellant; Mr Michael Shorrock, QC and Mr Howard Bentham for the Crown.
THE LORD CHIEF JUSTICE, giving the reasons of the court, said that the appeal against conviction was brought by leave of the single judge. The main evidence said to link the appellant with one of the rapes was DNA profiling which was crucial to the whole case. Failure on that count would inevitably mean failure on all counts.
The process of DNA profiling was extremely complex. Human cells in blood and in semen contained DNA. The process of DNA profiling started with DNA being extracted from the crime stain and also from a sample taken from the suspect.
In each case the DNA was cut into smaller lengths by specific enzymes. The fragments produced, which were radioactive, were sorted according to size by a process of electrophoresis. That involved placing the fragments in a gel and drawing them electro-magnetically along a track through the gel.
The fragments with smaller molecular weight travelled further than...
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R v Reed; R v Garmson
...it has been employed as a routine technique in the United Kingdom since 1987. The process as first used was described by Lord Taylor CJ in R v Deen (21 December 1993). In R v Doheny [1997] 1 Cr App Rep 369, Phillips LJ (as he then was) gave some general guidance about its interpretation, th......
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The Queen Complainant v Alexander Bonnett Defendant [ECSC]
...by the suspect. This process is complex…" 7 The process of DNA testing was succinctly described by Lord Taylor, CJ in Deen, The Times, January 10, 1994, and this description was adopted by Phillips, L.J. in Doheny and Adams, supra. I can do no better than to do the same. The learned Chief J......
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Presenting Probabilities in Court: The DNA Experience
...the Court has recently created a ‘DNA exception’ to its ‘no probabilities’ rule: State v Bloom 516 NW 2d 159 (1994). R v Deen The Times, 10 January 1994; R v Dalby (unreported, CA no. 94/2819/W2 (1995)); R v Adam 119963 2 Cr App R 467; R v Doheny. R v Adums The Times, 14 August 19%. Though ......