The Musical Comedy Murders of 1940:  

The creative team responsible for a recent Broadway flop (in which three chorus girls were murdered by the mysterious "Stage Door Slasher") assemble for a backer's audition of their new show at the Westchester estate of a wealthy ex-Broadway star.  The house is complete with sliding panels, secret passageways and a German maid who is apparently four different people – all of which figure diabolically in the comic mayhem that follows when the infamous "Slasher" makes his reappearance and strikes again – and again. As the composer, lyricist, actors and director prepare their performance, and a blizzard cuts off any possible retreat, bodies start to drop in plain sight, knives spring out of nowhere, masked figures drag their victims behind swiveling bookcases, and accusing fingers point in all directions. However, and with no thanks to the bumbling police inspector who snowshoes in to investigate, the mystery is solved in the nick of time and the "Slasher" unmasked – but you'll have to audition to find out who the "Slasher" really is.