| Chief Detective-Inspector Roderick Alleyn, CID | |
| Miss Van Maes | The success of the ship |
| Agatha Troy, RA | Of Tatler’s End House, Bossicote, Bucks. Painter |
| Katti Bostock | Well-known painter of plumbers and Negro musicians |
| Nigel Bathgate | Journalist |
| Lady Alleyn | Of Danes Lodge, Bossicote, Bucks; mother of Chief Detective-Inspector Alleyn |
| Cedric Malmsley | A student with a beard |
| Garcia | A sculptor |
| Sonia Gluck | A model |
| Francis Ormerin | A student from Paris |
| Phillida Lee | A student from the Slade |
| Watt Hatchett | A student from Australia |
| The Hon. Basil Pilgrim | A student from the nobility |
| Valmai Seacliff | A student with sex-appeal |
| Superintendent Blackman | Of the Buckingham Constabulary |
| Detective-Inspector Fox, CID | |
| Detective-Sergeant Bailey, CID | A fingerprint expert |
| Detective-Sergeant Thompson, CID | A photographic expert |
| Dr Ampthill | Police surgeon at Bossicote, Bucks. |
| PC Sligo | Of Bossicote Police Force |
| A charlady | |
| Bobbie O’Dawne | A lady of the Ensemble |
| An estate agent | |
| Ted McCully | Foreman at a car depot |
| Dr Curtis | Police surgeon, CID |
| Captain Pascoe | Of Boxover |
| His servant | |
