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Low Copy Number DNA analysis (LCN) - Prosecutors' checklist of questions


The following checklist of questions should be read in conjunction with the FSS General Statement on LCN DNA profiling which provides an assessment by the FSS on the reliability of the LCN technique generally.

The questions are designed to assist the police service and the Crown Prosecution Service to assess whether further, more detailed, information is required to support any particular prosecution in the light of the Judgement in the Omagh bombing trial, handed down on 20 December 2007.

The list of questions, as well as the general statement, should be regarded as discloseable material in the context of any trial in which they might be relevant.

The questions should be addressed to the prosecutor’s normal point of contact in the case.

  1. Professional standing
  2. Establish the qualifications of the forensic scientist responding to these questions. This should cover their experience in forensic science generally (e.g. in handling, examining and reporting upon exhibits) and their experience in DNA analysis in general and LCN in particular.

    Also establish the standing of the organisation which employs the scientist. Ask if the organisation is fully accredited to ISO 17025 in relation to its DNA analysis processes, and if that accreditation is up to date.

  3. Integrity of Exhibits and anti-contamination procedures
  4. What procedures were followed in the laboratory in order to maintain integrity and avoid contamination of items examined using the LCN techniques?

    What knowledge does the scientist have about the procedures which were followed to maintain integrity and avoid contamination from the initial collection of the exhibit, to its delivery to the laboratory and (if relevant) when it subsequently passed out of the control of the laboratory?

    Is the scientist aware of any gaps in continuity?

    Does the organisation have documented processes to monitor the testing environment before and after testing; were these followed in this case and were they fully documented in the laboratory report?

    Were the results checked against the organisation’s staff elimination database? If not, why not?

    Are there any special risks or considerations arising from exhibit integrity relating to this case?

  5. Commissioning LCN work
  6. How was the LCN analysis requested – was it at the request of the investigating officer or on the recommendation of the forensic scientist?

    Why was LCN thought to be appropriate in this case?

  7. Composite Results
  8. Does the evidence include composite results obtained by taking DNA information from different stains or sources (on a garment for example)?

    If so, then:

    How did the FSS derive the composite profile?

    Please provide a listing of the allele designations of individual sources in tabular form, with a brief explanation.

  9. Interpretation of LCN Profiles
  10. How were the LCN DNA profile results interpreted? Were there any departures from the normal interpretation criteria in this case?

    Please set out the interpretation by allele designation of each analysis in tabular form with a detailed description of the interpretation including any alleles that were not reported or disputed.

    Were there any variations or lack of reproducibility in the results? If so, please provide an explanation including the effect on the likelihood ratio (evidential value).

    Invite the scientist to explain what the results mean, in terms intelligible to the non-scientist, and the extent to which they answer two fundamental questions; whose DNA is it and how did the DNA get there?

  11. Retained Material
  12. Please list all extracts and material that has been retained following the LCN analysis.

  13. Inhibition
  14. Only if this case is one which arises from, or relates to, the Operation Cube initiative

    Might the phenomenon of inhibition be relevant in this case? If so, how has this been dealt with?

  15. Overall Assessment
  16. In the light of the verdict and circumstances of the Omagh Bombing Trial, and on the basis of the best available knowledge of different approaches to LCN DNA analysis, are there any potential weaknesses or areas of concern in this case not identified above?

22 January 2008

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