Complicating the matter was the presence of saliva from another dog, most likely Dog #01, on Kiwi #01.
An email from a senior DoC ranger to the laboratory stated the identity of both dogs involved in the attack would need to be "100 per cent confirmed" to be certain of a successful prosecution.
For that reason, and because of the cost of ongoing DNA tests, which had by then reached $6000, charges against the dog's owner were dropped.
Sue Reed-Thomas, DoC's Northland operations manager, said further DNA analysis was inconclusive, so the dog or dogs responsible could not be positively identified. The charges had been withdrawn.
No verified kiwi deaths had occurred in the area since then.
Ms Reed-Thomas said everyone related to the inquiry had assisted DoC with its inquiries, but the emails obtained under the OIA suggest tension between the department and the dog owners, or the dog owners' employers.
The emails were heavily redacted before being released so the full train of events is unclear. At one stage the owner offered to cover the cost of further dog DNA tests, but when DoC rangers arrived to take fresh saliva samples they were not allowed to be present while the samples were taken, so they could not verify which dogs they came from. As a result the second batch of samples could not be used to confirm the first.
A Massey University pathology report showed the dead kiwi comprised three females and two males, ranging in weight from 1.5 to 2.5kg. All but one had been in good condition prior to the attack. The sixth kiwi was not submitted for examination because it was too badly decomposed.
The six deaths were the most in one spate since at least eight kiwi were killed by dogs in the Wharau Rd area, near Kerikeri, in 2015.