My First Adventure (Some Unusual Knights and Knaves Part IV)

Inspector Craig left the island shortly after winding up the case of Arthur York. Two days later, I came to this island looking for adventure.

On the first day I arrived, I met an inhabitant and asked him: "Are you a knight or a knave?" He angrily replied: "I refuse to tell you!" and walked away. That's the last I ever saw or heard of him.

Was he a knight or a knave?

(Source: To Mock a Mockingbird and Other Logic Puzzles: Including an Amazing Adventure in Combinatory Logic by Raymond Smullyan)

He refused to give an answer and then proceeded not to give an answer. He is a knight.