Mmm, you think she was a plant? If she was, I doubt she realised it, and I would have thought they'd have fed her some false information for her to spill.

She's a recent Hogwarts graduate. Ravenclaw House, I think. Barty's got someone on it. She's the same class as Barty's foster sister, Narcissa's niece, but I believe that young lady was in Hufflepuff, wasn't she? Anyway Barty's got someone checking on her friends and acquaintances.

As far as statements go, probably best at this point to say we caught the person who made the statement and she's made a full confession, and leave it at that. It would be nice to say she was working alone, but we'll look like fools if someone else writes in Charlotte's diary an hour later.