Wiktionary
you tell me
interj. (context in response to a question English) I don't know!
Usage examples of "you tell me".
Now, miss, can you tell me how it's come about that Washington's mixed up in this, and within a bare couple of hours of Glens Falls getting the first report?
On the other hand, from what you tell me, if you do put Ashley on the stand, Brennan can destroy her.