Can the defence test DNA again?

Yes.

DNA evidence can be re-examined, reinterpreted, or subjected to further testing.

This does not always mean repeating the exact laboratory process. Independent review may involve examining how samples were collected, what was tested, and whether additional or different testing could provide further information.

In some matters, unused samples remain available for further analysis. In others, the focus may be on reviewing DNA profiles, statistical interpretation, and how results were reported rather than conducting new laboratory work.

Further testing may be considered where mixed DNA profiles are present, where low-level DNA has been detected, where sampling was limited, or where new questions arise about transfer, persistence, or timing.

Decisions about additional testing depend on the condition of exhibits, the amount of biological material remaining, and the relevance of further analysis to the issues in the case.