Some muted thoughts on the legal issues involved in the search of Nicky Hager's house, with only limited added outrage. That may come later.
First of all, the Police are investigating a real crime here. Even certain bloggers whom we do not name have a right to keep others out of their computer systems, and this right is protected by criminal sanction.
As such, the Police do have the legal right to obtain a search warrant to try and get evidence that may help them identify who "Rawshark". It isn't entirely unreasonable to think that Mr Hager's data devices might have some information on them that helps with that identification.* I'm sure he's been very, very careful to try and avoid leaving anything that will assist in that way ... but maybe he's slipped up and failed to eradicate all such traces (if it is even possible to do that these days).
Of course, a "legal right" is not the same thing as a "legal duty" to act. The police have investigative independence, so nothing says that they must search Mr Hager's property (and take away his devices and materials) in this way. Furthermore, Mr Hager is not a suspect in any offending - he's an "innocent witness", in the sense that he's simply lawfully** in possession of information that might help with identifying the hacker.
So the Police could instead have decided to approach Mr Hager, see if he'd be willing to talk to them about his dealings with Rawshark, and from that conversation decide whether they think there's any realistic chance of them finding any material still in his possession that would help with their inquiries. Such a conversation hardly would have tipped Mr Hager off - he full well knew of the Police's possible interest in him - but it could have helped decide whether a full search with 5 officers and subsequent removal of a considerable amount of gear and files was needed.
However, that's not what they've done. Instead, they've taken a whole lot of data devices and files away with them. What now happens to all of that?
Well, under the Search and Surveillance Act, certain sorts of "privilege" are recognised. One of these "privileges" is that conferred by the Evidence Act on journalists who wish to avoid disclosing the identity of a confidential source. This privilege exists for a reason - unless such sources can have some confidence that journalists will not be forced to disclose their identity, they will be less likely to provide the sort of important information that can aid in discussion of matters of public interest.
If a search is being carried out that may conflict with this privilege, a special procedure exists. First of all, the person who claims the privilege must tell the Police (or other body conducting the search) that they think it exists. That doesn't in itself stop the search; rather, anything that is obtained from the search is parcelled up unexamined and given over to the High Court to look after. The High Court then examines the claim of privilege, and if it applies, gives the material back to the person who it was taken from ... otherwise, the Police (or other agency) gets to have a look at it.
Which is what is now going to happen with regards Mr Hager. Which in turn raises two questions:
(1) Is Mr Hager a "journalist" in terms of the privileges conferred by the Evidence Act (because only "journalists" can claim the right to keep their sources confidential). All I'll say on this is it would be a moral outrage if the courts were to regard the work he does as "not journalism", while that of a certain blogger whom we do not name has been deemed "journalism" (albeit not being worthy of any legal protection).
(2) Is this a situation where the privilege journalists generally enjoy under the Evidence Act should be set aside because of "public interest in the disclosure of evidence of the identity of the informant"? That is an express balancing test - how important is it to try to unmask Rawshark, in light of the potential damage that accessing Mr Hager's materials might do to his (and other media's) ability to do their jobs properly?
Needless to say, I'm sympathetic to Mr Hager's position here (while also thinking that there's almost zero chance that there's anything in the material the Police took away that will help with their case). So I hope he wins it. It's just a shame he has to fight it at all.
* I set to one side the question of whether the way the Police chose to conduct their search in this particular case was "reasonable" in terms of s.21 of the New Zealand Bill of Rights Act ... while noting it is a live issue.
** For a full and informative discussion of Mr Hager's potential legal liability in criminal and civil law, see this discussion at the University of Otago.