"He knew he should have treated the animals for parasites, but he didn't."
The driver of the car was uninjured.
The two people were found dead near Mere Road in Lake Taupō last Friday.
Three helicopters were on site.
More to come.
The crash happened just before midnight.
For the first time in New Zealand a regional council has transferred some of its functions to an iwi.
Emergency services are at the scene.
Two homes were destroyed in five early-morning fires earlier this month.