On 2 October last year, five detectives and a police computer expert spent ten and a half hours raiding my home. They took all of the phones, computers, hard drives, USB keys, CDs and other electronic devices, as well as an assortment of files. They were trying to uncover the identity of a confidential source who had given me information for my recently published book about New Zealand politics. The book had revealed a campaign of dirty tricks being run out of the prime minister’s office, including an organised system for smears on political opponents.