"We are glad to finally be able to hold those responsible to account.
"We hope that it will bring some closure to Mr Harris' friends, whanau and to the Whangarei community," he said.
Mr Miller said enquiries were still continuing and further arrests were likely.
"I would like to acknowledge the assistance provided by the public and the dedication of the investigation team who have worked tirelessly over the past five months on this inquiry.
"We are also still welcoming any further information relating to the case, and would like to hear from anyone with information that may assist," he said.