Ichiro, Sano: a samurai and private investigator for the shogun in Edo, Japan by Laura Joh Rowland

Ikmen, Cetin: a policeman in Istanbul, Turkey by Barbara Nadel

Iles, Desmond: detective constable in an English seaport by Bill James

Iliona: high priestess blackmailed into spying for Sparta, in 5th century BCE Greece, by Marilyn Todd

John Ingram: in South Pacific thrillers, by Charles Williams

Ingram, Nelson: a burnt-out reporter  back-digging up the dark criminal secrets that hide beneath the sleepy surface of Litchfield, Alabama by Stephen J. Clark

Jack Irish: lawyer and gambler, turned debt collector and people finder, in Melbourne, Australia, by Peter Temple

Isaac, blind physician in 1350s Girona, Spain by Caroline Roe

Ives, Hannah: a breast-cancer survivor and a down-sizing victim in Annapolis, Maryland by Marcia Talley

Ivory, Kate: a novelist turned amateur detective in Oxford, England by Veronica Stallwood