Name the character

In our—slightly—new quiz for 2022, can you guess the fictional character from these clues (and, of course, the fewer you need the better)?

1. He’s the only fictional character ever to have an obituary in the New York Times.

2. The obituary followed his death in the 1975 novel Curtain.

3. It explained that he became a famous private investigator after retiring from the Belgian police force in 1904.