[Spoiler] Possibility regarding the DNA tests
If Tui's baby belonged to Al or one of the other members of his ring, and if Al was ordering a DNA test for Johnno as well (which seems strange to begin with), do you think he could have just swapped the results?
Johnno's DNA test would show him to be Matt's child, and the baby's would show him to be someone else's. In that case, the investigation into who raped Tui would still be open. But if Al just switched the samples, that would close the case on Tui's baby (Matt's the father) and Johnno would just be left with unanswered questions. He wouldn't have the resources to do an investigation into his "real" father's identity, so the matter would be dropped.
Any thoughts?