When should DNA evidence be reviewed?

DNA evidence can be reviewed at any stage of a matter, including after charges are laid or as a case progresses toward trial. However, it is often most valuable when reviewed early, particularly where it forms a central part of an allegation.

Early review allows preliminary assessment of how samples were collected, what was tested, how results were interpreted, and whether important issues — such as transfer, persistence, contamination, or statistical interpretation — have been fully considered. This type of initial evaluation can assist legal teams in developing case strategy, including decisions about further testing, lines of enquiry, and, in some matters, plea negotiations.

In some cases, opportunities for additional testing, targeted sampling, or clarification of findings exist only in the early stages. Once exhibits have been stored, consumed, or finalised, those options may become more limited.

That said, DNA evidence can still be meaningfully reviewed later. Reassessment of DNA profiles, statistical interpretation, reporting language, and the assumptions applied during analysis can occur at any point in proceedings, including close to trial.

Review may be particularly important where mixed DNA profiles are present, where semen or trace DNA findings are relied upon, where timelines are uncertain, or where the wording of a report appears stronger than the underlying science supports.