Bad Blood is a 1981 British-New Zealand thriller film set during World War II in the small town of Koiterangi (now Kowhitirangi) on the west coast of the South Island of New Zealand, and is based on the factual manhunt for mass-murderer Stanley Graham. The film was directed by English director Mike Newell, who went on to direct Four Weddings and a Funeral. Much of the film was shot at the original locations. The script was based upon Manhunt: The Story of Stanley Graham, by H. A. Willis (Whitcoulls, 1979) and adapted by New Zealand-born Andrew Brown.
In October 1941 Stan Graham, a Westland smallholder, develops a persecution complex and starts to threaten his neighbours, in which he is encouraged by his wife. He then refuses to conform to a government order for all citizens to surrender their firearms for the duration of the war. Eventually a party of four policemen arrive to confiscate his firearms, which causes a flashpoint for Graham. With the help of his wife who shoots and injures one of them, Graham shoots and kills all the policemen and, in the ensuing altercations, three locals also. Shot and injured himself, Graham then heads into the surrounding forest. A manhunt is organised, involving police, army and local home guard members, and finally they track him down.