“Might be a Major,” said Mr. Blore. “No, I forgot. There’s that old military gent. He’d spot me at once.” “South Africa,” said Mr. Blore, “that’s my line! None of these people have anything to do with South Africa, and I’ve just been reading that travel folder so I can talk about it all right.”

Having been invited to the island to investigate the guests, Blore decides he needs a false identity and disguise. Since he knows that one of the guests was in the military, he realizes that he can’t fake a military career. His hastily assembled narrative as a visitor from South Africa underestimates how much factual detail he will need to know. Lombard, who actually has been to South Africa, spots Blore’s deception at once.

With a quick movement Blore was beside him. He said: “If you’ll just let me have a look.” He twitched it out of the other’s hand, and ran his eye over it. He murmured: “Coronation machine. Quite new—no defects. Ensign paper—the most widely used make. You won’t get anything out of that. Might be fingerprints, but I doubt it.” Wargrave stared at him with sudden attention.

Blore has not yet revealed his true identity as a former police inspector to the other houseguests when someone presents a typed letter purportedly from their host, U.N. Owen. Without thinking, Blore snaps into detective mode and makes several quick observations about the letter. Wargrave seems surprised and impressed, as though he didn’t expect Blore to be so capable. Wargrave brought Blore to the island to punish him but now worries he’ll identify the murderer.

Blore said forcefully: “I don’t know where the revolver is, but I’ll bet I know where something else is—that hypodermic syringe. Follow me.” He opened the front door and led the way round the house. A little distance away from the dining room window he found the syringe. Beside it was a smashed china figure—the sixth broken soldier boy. Blore said in a satisfied tone: “Only place it could be.”

Once again, Blore uses his detective skills to solve one of an ongoing set of mysteries: the location of a syringe used in one of the murders. Although momentarily satisfying, this information ends up being useless. The crime has already been committed, and where the murder took place was never a mystery. On the other hand, the revolver’s location seems extremely important at this juncture, and finding the gun might prevent another murder.

He started off into the moonlight. Blore, after a minute’s hesitation, followed him… After all he had tackled criminals armed with revolvers before now. Whatever else he lacked, Blore did not lack courage. Show him the danger and he would tackle it pluckily. He was not afraid of danger in the open, only of danger undefined and tinged with the supernatural.

The narrator explains Blore’s mindset as he tracks Armstrong after he quietly leaves the house. Blore believes that Armstrong’s sneaky behavior implicates him, and Blore also believes Armstrong carries a gun. Despite being a detective and former policeman, the events of the past few days, including now six murders, have started to make Blore feel rather frightened and unsure of himself. However, now that Blore believes he has a culprit to tackle, he feels prepared to put an end to the killings.