Reed & Anor, R v

Factual and Procedural Background

This opinion concerns appeals against convictions in two separate criminal cases heard by the Court of Appeal (Criminal Division) in the United Kingdom. The appellants were convicted in August 2007 on charges including murder and sexual offences, with key evidence relying on DNA profiling, particularly Low Template DNA (LTDNA) analysis using the Low Copy Number (LCN) process. The appeals arose from challenges to the reliability and admissibility of DNA evidence obtained through this process, as well as other evidential and procedural matters.

In the first case, two appellants were convicted of the murder of an individual who was stabbed multiple times at his home. DNA profiles matching the appellants were found on fragments of plastic believed to be parts of knife handles near the victim’s body. The defence raised an alibi and challenged the expert evidence concerning the manner and timing of DNA transfer onto the knife handles.

In the second case, the appellant was convicted of offences including kidnapping, rape, and sexual assault. DNA evidence derived from multiple biological samples related to the complainant was analysed using the LCN process. The appellant challenged the reliability of the DNA evidence and the trial judge’s directions to the jury.

The appeals were listed together for hearing, with extensive expert evidence heard de bene esse regarding the scientific validity of Low Template DNA analysis and the scope of expert opinion on DNA transfer mechanisms. Fresh evidence was sought to be admitted under section 23 of the Criminal Appeal Act 1968 but was ultimately declined.

Legal Issues Presented

1. Whether DNA evidence derived from Low Template DNA using the LCN process is sufficiently reliable and admissible in criminal trials, particularly regarding the scientific validation of the process and interpretation of partial or mixed DNA profiles.
2. The extent to which expert witnesses may give evaluative opinions on the possible mechanisms and timing of DNA transfer when the biological material is unidentified cellular material.
3. The admissibility and scope of expert evidence concerning DNA match probabilities and the limitations inherent in such evidence.
4. The adequacy and fairness of the trial judge’s directions to the jury on issues including alibi, the absence of certain witnesses, and the interpretation of expert evidence.

Arguments of the Parties

Appellants' Arguments

• The appellants initially challenged the general reliability and scientific validation of the DNA evidence obtained using the LCN process, citing limited research, absence of protocols, and disputed interpretation.
• They contended that expert evidence evaluating the manner and timing of DNA transfer was inadmissible because the biological material was unidentified and the scientific basis for such evaluations was insufficiently reliable.
• Specifically, it was argued that the expert witness’s opinion that the appellants had handled the knives when they broke was speculative and beyond the proper scope of expert evidence, amounting to an impermissible direction to convict.
• Challenges were made to the trial judge’s summing up, including alleged misdirection regarding the burden of proof, the absence of certain witnesses, and the interpretation of mobile phone evidence and other non-DNA points.
• In the sexual offences case, it was argued that the match probabilities based on minor DNA profiles were unreliable and that the judge failed adequately to direct the jury on the limitations of the DNA evidence, especially regarding mixed profiles and potential multiple contributors.

Respondent's Arguments

• The Crown maintained that the LCN process was scientifically valid for quantities of DNA above the stochastic threshold (100-200 picograms) and that the DNA profiles in these cases were reliable and interpretable.
• It was submitted that expert evidence enumerating and evaluating possible mechanisms of DNA transfer was admissible where there was a sufficient evidential basis, including knowledge of the crime scene and quality of the DNA profiles.
• The Crown argued that the expert’s evaluative opinions were properly qualified and did not amount to impermissible advocacy or directions to convict.
• The trial judge’s directions to the jury were defended as clear, comprehensive, and fair, adequately addressing the burden of proof, the absence of witnesses, and the complexities of the DNA evidence.
• Regarding the sexual offences case, the Crown contended that the DNA evidence and match probabilities were properly admitted and that the jury was correctly directed on their limitations and significance in the context of the whole case.
• The Crown opposed the admission of fresh expert evidence under section 23, arguing that it was either available at trial or would not have affected the safety of the convictions.

Table of Precedents Cited

Court's Reasoning and Analysis

The court undertook a detailed and methodical analysis of the scientific principles underlying DNA profiling, particularly Low Template DNA and the LCN process. It acknowledged the evolution of DNA forensic techniques and the challenges posed by analyzing minute quantities of DNA, including stochastic effects such as allelic drop-out and drop-in, and the interpretation complexities of mixed DNA profiles.

The court accepted the expert evidence, particularly that of Professor Caddy and Dr Linacre, that the LCN process is scientifically valid and capable of producing reliable DNA profiles when the quantity of DNA analyzed is above a stochastic threshold estimated between 100 and 200 picograms. The court emphasized that challenges to the validity of the LCN process should not be permitted at trial absent new scientific evidence and that quantification of DNA prior to analysis is now standard practice.

Regarding expert evidence on the transfer of DNA, the court distinguished between enumerating possible mechanisms of transfer and evaluating those possibilities. It held that it is admissible for a forensic expert with appropriate experience to enumerate and evaluate possible transfer mechanisms, including primary, secondary, and tertiary transfer, provided appropriate caveats are given and the limitations of the science are made clear. The court rejected the contention that such evaluative evidence was inadmissible due to insufficient scientific development.

The court found that the expert evidence given by Valerie Tomlinson was admissible in its enumerative and evaluative parts, though it rejected her opinion that the appellants were handling the knives when they broke, as that went beyond the scope of proper expert evidence. The court noted that no objection was raised at trial to this impermissible part of her evidence and that its exclusion would not have affected the jury’s verdict.

The court considered and rejected the criticisms of the trial judge’s summing up on non-DNA issues, including directions on the burden of proof, the absence of witnesses, the interpretation of mobile phone evidence, and the handling of evidence relating to clothing. It concluded that the summing up was clear, balanced, and fair.

In the sexual offences appeal, the court analyzed the DNA evidence from various biological samples and the expert evidence on match probabilities and mixed profiles. It found that the trial judge had properly admitted the DNA evidence and had given comprehensive and appropriate directions to the jury on its limitations and significance. The court rejected the appellant’s arguments that the evidence should have been excluded or that the jury was misdirected.

The court declined to admit fresh expert evidence under section 23 of the Criminal Appeal Act 1968, reasoning that the evidence was either available at trial or would not have affected the safety of the convictions.

Holding and Implications

The appeals are dismissed and the convictions are upheld.

The court held that Low Template DNA evidence obtained using the LCN process is admissible and reliable when the quantity of DNA analyzed exceeds the stochastic threshold of 100-200 picograms. Expert evidence enumerating and evaluating possible mechanisms of DNA transfer is admissible with appropriate qualifications and caveats. The trial judge’s directions to the jury were fair and adequate, and the fresh evidence sought to be admitted on appeal was refused.

The direct effect is that the convictions in both cases remain safe and are not disturbed. The decision clarifies the standards for admissibility and evaluation of Low Template DNA evidence in criminal trials, emphasizing the importance of expert qualifications, scientific reliability, and procedural safeguards in the presentation of complex forensic evidence. No new legal precedent beyond the application of established principles to Low Template DNA evidence is established.