He probably knows a lot more than that.
3 seconds sound clip from the The Third Man (1949) movie soundboard.
You can hear this line at 00:41:06.110 in the Blu-ray version of the movie.
Quote context
[...]
- You'll never teach these Austrians to be good citizens.
- It was his duty to give the evidence.
- Even so, he remembers wrong.
- Harry was dead before you got him to that statue.
- He probably knows a lot more than that.
- The police say he was mixed up in some... racket?
- Oh, that's quite impossible. He had a great sense of duty.
- Your friend Kurtz seems to think it was possible.
- I understand how an Anglo-Saxon feels. The Baron hasn't travelled, you know?
- He seems to have been around a bit.
[...]