[Well, that narrows it down greatly. The only people who knew where the sword had been hidden were her, Squalo, and whoever had hidden it in the first place. Squalo would have shown his face by now, and probably would have made some kind of snarky comment at some point, so odds are, it wasn't him. This left whoever had hidden the sword, and given that (out of Mammon and Belphegor) only one of the suspects had some kind of motive...]
[Voice]
Mammon, I presume?