What do Blore, Lombard, and Armstrong uncover as they search the island for this lunatic? **And then there were none**

Blore, Lombard, and Armstrong search the island from top to bottom in search of the murderer.  Unfortunately for them, they find absolutely nothing.  They disocver that they are completely alone on the island and the only possibility is that one of the remaining guests is the murderer.  This is an important part of the novel, because it's the moment when we realize that the situation is utterly hopeless.  There isn't anyone coming to help and the murderer is playing off of everyone's fear.  Some may consider this the climax or turning point of the novel since it is a scene of maximum intensity.