maybe one of the dove shells, like a sparse dove shell. Seems like the Anachis spp. would be a good place to look. Dove shells, (weird they call an animal a "shell" isn't it?), are from the Columbellidae family, and aren't thought to be predatory. Maybe start with Anachis sparsa on a google search and see what the close relations are like, the problem is they have variable patters, so the colors won't matter, it will be the ridges and the tooth around the opperculum and those kind of things that separate them.