| 1 | Hercule | Poirot | Famous Belgian detective. |
| | Sylvia | Rule | Clarence's widow. Receiver of the letter. |
| | Barnabas | Pandy | Victim. Deceased. aka: Grandy. |
| | Eustace | Campbell-Brown | Mildred's fiance. |
| | George | | Hercule's servant. |
| | John | McCrodden | Receiver of the letter. |
| | Rowland | McCrodden | Solicitor. John's father. aka: Rope. |
| 3 | Annabel | Treadway | Receiver of the letter. Barnabas's granddaughter. |
| | Lenore | Lavington | Annabel's sister. Timothy's mother. |
| | Hopscoth | | Annabel's dog. aka: Hoppy. |
| 4 | Euphemia | Spring | Young waitress at Pleasant's Coffee House. aka: Fee. |
| | Edward | Catchpool | Hercule's friend. |
| | Philippa | | Fee's co-waitress. |
| | Hugo | Dockerill | Hugo's wife. |
| | Timothy | Lavington | Barnabas's great-grandson. Lenore's son. |
| | Ivy | Lavington | Timothy's sister. |
| | Freddie | Rule | Sylvia's son. |
| 6 | Nathaniel | Bewes | Edward's superintendent from Scotland Yard. aka: The Super. |
| | Emerald | Mason | Rowland's secretary. |
| | Cecil | Lavington | Lenore's husband. |
| 7 | Peter | Vout | McCorden Firm's senior partner. Barnabas's solicitor. |
| | Vincent | Lobb | Barnabas's former enemy. |
| 9 | Mildred | | Sylvia's daughter. |
| | Kingsbury | | Barnabas's manservant. |
| 12 | Stanley | Donalson | Rowland's co-partner. |
| 13 | Blanche | Unsworth | Edward's landlady. |
| 14 | Skittle | | Annabel's dog. |
| 16 | Mrs. | Rope | Rowland's wife. Deceased. |
| 20 | Catalina | | John's Spanish lady friend. |
| 23 | Deborah | Dakin | The widow of Vicent's eldest son. |
| 24 | William | Evans | The man who stole the slate. |
| 33 | Hubert | Thrubwell | Local police officer. |
