Sir Thomas Legge, the Assistant Commissioner at Scotland Yard is peaking with Inspector Maine about Soldier's Island. They can't understand how there could be ten people dead on an island and no survivors. Legge wants to know who killed them, but there's very little evidence. Wargrave and Lombard were shot, Miss Brent and Marston died of cyanide poisoning, Mrs. Rogers died of an overdose of chloral, Rogers head was split open, Blore's head was crushed, Armstrong drowned, Macarthur's skull was fractured, and Vera was hanged.
Scotland Yard is trying to solve the mystery, but they do not have much more evidence than the reader. They cannot figure it out.
The Sticklehaven (mainland) people don't know anything except the fact that the island was owned by a Mr. Owen and all the arrangements were made by a man named Isaac Morris. And Morris is also dead. They know that he was mixed up in the drug business and was also involved in financial scandals. He was able to cover the financial tracks of his employer, Mr. Owen.
Isaac Morris left no trail and no clues. Even with knowledge that the guests on the island did not have, Scotland Yard still cannot figure out the mystery.
The Sticklehaven townspeople did not notice anything strange because the millionaire who owned the island before always used to have crazy parties. They had come to expect strange events from the island.
The murderer planned well to make sure that no one would interfere.
Fred Narracott tells the police that he was surprised by the people in the party who went to the island. The fact that they were all so normal and quiet led him to violate Mr. Morris's orders and take a boat to the island to check out the SOS signals they had been sending. The signals were seen by some boy scouts on the mainland on the 11th but they could not get there until the 12th because of the rough seas.
The fact that the guests were of mixed classes and did not seem like the friends of millionaires was the real warning signal. With all of the other strange things going on this shows how powerful class structures are in this society.
The gramophone record they found on the island was made by a theatrical company and sent to U. N. Owen, care of Isaac Morris. It was understood to be a part of an amateur performance of a new play. Inspector Maine says he has investigated everything as far as he could.
Every single detail was thought out. The murderer left no tracks.
Maine then tells Legge about the accusations against all of the guests on the island. He mentions that Seton, who Wargrave convicted, was found later to really have been guilty. He also says that Isaac Morris died on the night of August 8th when he took an overdose of sleeping pills; there was nothing to show whether it was an accident or suicide. Legge thinks that the death of Morris must be related.
Wargrave is the only person on the island who really was not guilty. Even though Isaac Morris was not on the island he was still a victim of the murderer.
Maine says that they do know why everyone was killed. It must have been some person who was fanatical about justice. He picked ten people who were beyond the reach of law. He killed them and disappeared from the island. But it also could have been someone on the island.
They realize that the murders were all committed out of a sense of justice – someone was taking the law into his or her own hands.
They do have some evidence from the diaries kept on the island by Vera, Emily Brent and some notes by Wargrave and Blore. The death occurred in this order: Marston, Mrs. Rogers, Miss Brent, Wargrave. Blore then has a note “Armstrong disappeared.”
The number of clues left behind such as the diary entries from the guests makes it seem like they should be able to figure out who the murderer is.
Legge thinks that this must mean that Armstrong killed the others and tried to swim out. But Maine tells him that Armstrong's body was dragged above the high water line. Then the people left were Vera, Blore and Lombard.
But every theory is contradicted by another clue. This is similar to what would happen on the island when the guests were making wild guesses to figure out who the murderer was as well.
Another piece of evidence is that the revolver was found in Wargrave's room with fingerprints on it. Then it seems like Vera could have pushed the statue on Blore, shot Lombard and hung herself. But there is one problem with this theory: the chair wasn't found kicked over. It was neatly put against the wall. So someone must have replaced the chair after Vera's death.
There was clearly someone alive on the island after Vera's death. But it seems clear that everyone was dead by the time Vera hanged herself.
Therefore it seems like there must have been someone else on the island. But the Sticklehaven people are sure that no one could have left the island before the rescue boat came. So they have no idea who committed the murders.