Yes, Negoro was an evil being, but must they conclude from that that he was a criminal?
It was painful to Dick Sand's character to go as far as that.

And, meanwhile, could suspicion rest on any other?
No, those honest negroes had not left the grotto for an instant, while Negoro had wandered over the beach.

He alone must be guilty.

Dick Sand then resolved to question Negoro, and, if necessary, have him searched when he returned.

He wished to know decidedly what to believe.
The sun was then going down to the horizon.