Wiktionary
caught in the cookie jar
a. (alternative form of caught with one's hand in the cookie jar English)
Usage examples of "caught in the cookie jar".
He pulled the noose off his head, the jute catching in his hair and tugging, doing it quickly, like a child caught in the cookie jar.
The two of them were playing footsie at a table, and when I noticed it, Marty pulled away from the guy--sort of like a kid with his hand caught in the cookie jar.
Lenore's expression was disapproving, but it seemed only the mild censure one might display to a little brother caught in the cookie jar.