Lawyers acting for the police and the Government Communications Security Bureau have requested recordings and transcripts made by the author of a book about Kim Dotcom.
Herald journalist David Fisher received the legal letter from Crown Law this week and has been given until Friday to respond.
The request for information relates to the $6 million civil case Dotcom is taking against the GCSB and police over the unlawful raid and illegal spying carried out on him and others.
He wants compensation for those actions and alleges police used an "excessively aggressive and invasive approach", while the claim says the spy agency should have known the Dotcoms were not to be spied on.
The letter, from Crown lawyer Aedeen Boadita-Cormican, said matters referred to in the book "lead us to believe that email communications with the plaintiffs ... contain information relating to the events which are the subject of these proceedings".
The full letter is here. It seems to be unprecedented in New Zealand for police to seek journalistic materials from a writer, and journalists will refuse in order to ensure that they can continue to effectively gather the news. The question is whether this is more than a try-on - will the police and spies take it to court, and if so, will the courts uphold the public interest in people being able to talk to journalists without fear that the reporter will later be press-ganged into serving as a police spy?