Two of the later films are based on the novels:
1. Charlie Chan's Murder Cruise (based on Charlie Chan Carries On)
2. Charlie Chan in Rio (based on The Black Camel)
Both are good films, but not as good as earlier versions of the stories (Eran Trece, The Black Camel).
If only the lost film Charlie Chan Carries On would turn up somewhere! In the meantime, at least the Spanish language film (Eran Trece) still exists.