They didn't spend 10 years sitting around waiting to complete an arson investigation. They completed an arson investigation and couldn't prove it was a deliberate fire.
As the murderer bragged to the undercover officer, her choice of arson method was rather clever as it was very hard to distinguish from an accidental fire - our fire brigades run periodic campaigns reminding men who live alone to not "drink and fry" because of accidental oil fires, that do occasionally kill older men who live alone.
So, yeah, you made an assumption that they spent 10 years doing nothing, when they most likely spent 10 years identifying the suspect, gathering enough evidence to convince a judge to give them a warrant for cellular phone tracking data, then a warrant for surveillance, then getting an undercover officer into position to gather more evidence, so that they had enough evidence to bring a prosecution with a reasonable chance of success.
That's the thing about murder in New Zealand, the CIB[0] aren't backed up in homicides, so they'll always come back to open cases. Very hard to get away with murder here for that reason.
For example... ...this man was found guilty 25 years [1] after the crime, other people involved are on trial now [2].
And in a grim footnote, the convicted murderer discussed in the article appears to have committed suicide the day after her conviction. [3]
[0]: https://en.wikipedia.org/wiki/Criminal_Investigation_Branch
[1]: https://stuff.co.nz/national/crime/119880348/jeremy-powell-a...
[2]: https://stuff.co.nz/national/crime/301012985/detective-accus...
[3]: https://stuff.co.nz/national/crime/133338228/arson-killer-ly...
Edit: the reason I ask is not simple curiosity, but to clarify your remarks, specifically, "It worked fine," by which I assume you mean, you did not ultimately get convicted of the suspected crime. If you are an entirely innocent party, it would seem unlikely that something you could have said would incriminate yourself (plus you probably have some other exculpatory evidence). The only reason your silence in the car "worked fine" would be if you avoided making statements that would signal your guilt.
This is, uh, naive.
joking aside, it is weird to me that privacy of someone can be invaded to such a degree when you are presumed innocent. like, ok it leads to some arrests but how many thousands of attempts were about bugging innocent people's homes for nothing?
I get it murder is fucked but 22kh of recording and undercover?
I thought they would do that only to 'higher' people
The rest is recordings and we have no idea how long they are. Probably a new one every time there is a pause. So maybe a month's worth.