Black velvet evening gown with crystal belt

Last night around 7:20pm, I realized my black velvet evening gown was missing. It's an Alex Evenings gown, size 6, floor-length with a crystal-embellished belt. I wore it to a charity gala and stepped outside for a breath near the Palace Theatre on Clinton Avenue around 7:15pm; I think someone picked it up after that. The gown is in great condition, except for a tiny snag on the left hem and a faint blue tint on the lining from store lighting. It was a gift from my grandmother and really means a lot to me; I’d be forever grateful to have it back.