In the novel Postern of Fate, Inspector Norris is a police Officer working in Hollowquay. He is in charge of the investigations into the killing of Isaac Bodlicott and later the shooting of Tuppence Beresford.
Cryptically, he tells Tommy that various people might be turning up at his house offering to help with gardening. There might be one probably named Crispin who claims he used to work for Mr Solomon. Norris tells Tommy anyone who mentions Solomon is all right and anyone who does not isn't.
Late in the story, in a conversation with Colonel Pikeaway, Tommy Beresford remarks that he has not seen Inspector Norris around and he is probably new to the area. Pikeaway doesn't reveal much but does say that he knows all about Norris. He also adds that if one goes by what Norris says, one would be going right. This suggests that Norris is a picked officer perhaps from Special Branch sent to take charge of things at Hollowquay.