Green’s Dictionary of Slang

rumble n.1

[rumble v.2 (1)]

1. [1900s–60s] the act of discovery, usu. in the context of a crime.

2. [1910s–50s] an alarm (during the course of a crime).

3. [1910s+] a warning, a piece of information.

4. [1920s] (US Und.) an accident, a problem.

5. [1960s+] (US) a rumour.