He did not know names or places--knew only that the man would be found waiting at a certain place, and was not white.
"How did you get that information ?" Fred demanded.
"By listening." "When?
Where ?" "At night, months ago, in Nairobi, outside the professor's tent.

I lay under the fly among the loads and listened.

The man came in the dark, and went in the dark.

I did not see him.

I did not hear him called by name.