One murder. One victim. 47,000 suspects.

Cremorne, Sydney, 6:08 AM Sunday. Marjorie Devlin, seventy-two, retired Sydney Ferries traffic-coordinator, lies head-first on the bluestone back step at 23 Cremorne Road. Inspector Hartmann opens her commuter-pass register: forty-three years of ferry passengers, 47,000 first names, seventeen clues, one killer.

Bulimba, Brisbane, 4:50 AM Friday. Patricia 'Pat' Halloran, seventy-four, retired Queensland Land Registry counter-clerk, lies head-first on the basalt retaining wall below her own garden path on Hawthorne Street. Inspector Hartmann opens her wax-cloth counter-clerk notebook: forty-one years of Land Registry counter-records, 47,000 first names, seventeen clues, one killer.

Carlton North, Melbourne, 6:25 AM Tuesday. Eleanor 'Nell' Fitzgerald, seventy-one, retired NGV registrar and State Library volunteer, lies on the slate-paved rear courtyard of 47 Canning Street. Inspector Hartmann opens her three buff folders: thirty years of NGV, RHSV and SLV records, 47,000 first names, seventeen clues, one killer.