Well no, but we do know she fired her gun at the end of ep three (Ryu confirmed this, though I guess was vague on the specifics) and also that pieces shouldn't be able to do what their real characters couldn't.
As for the mystery, having never read any mysteries I found it quite enjoyable (though I accept it was cliche, however Ryu sort of implied he knew that and was waiting for people to figure it out to crank up the difficulty, but the audience at large did not). Aside from that it was an interesting tale with a good message, a new take with the whole lying in narrative thing, and also it was solvable for the most part. So i would say not too bad on the whole.