Books with: Mystery-solving/adventuring kids in adulthood

[...cats?]

Looking for books about adults who used to have adventures/solve mysteries/etc. as children. For example: The Boy Detective Fails, Meddling Kids, and the movie "The Kid Detective". Adult fiction preferred, thanks!

[Celia]

It’s not a book, but there’s a play called “the solve it squad” that’s an adult scooby soo parody

[...cats?]

Bump

[SamSpayedPI]

It by Stephen King might work in the category.