No Corpse by Nancy Sanra

A perfect vacation. A cruise ship filled with women expecting fun, new adventure and romance. The Caribbean in full beauty. But suddenly everything changes. A deadly killer moves undetected through the ship murdering at will...but leaving few clues. The early signs point to a group of college roommates with a crowd of old ghosts to deal with. The ship's chief of security, wants and finally gians private investigators Tally Mcginnis and Cid Cameron's big-city expertise, but even as they pursue the killer the bloodbath continues. And someone wants Tally dead.