Is it a White is Right nutter? Urban Maori were excluded from the lucrative fisheries settlement--perhaps an urban activist. Then again, it could have been an opportunistic grab, and the abductor was very unlucky to have kidnapped the child of a prominent couple. Is it the original family of the adopted daughter?
To make things juicier, on the same day there was a murder ("garotted or knifed") in the same part of town.