Beautiful, featherheaded April Delavan's boyfriend Jeff Feldman, a slimy potter/con artist old enough to be her father, has gone missing, and April wants him backor at least the $18,000 he glommed from her before he left. But Cleveland Heights p.i. Milan Jacovich, in a sixth outing, swiftly discovers that the only people who care where Feldman went, or even whether he's dead or alive, are his potential customers for a 250-year-old ceramic vase last seen in Nazi Germany. Feldman's client list includes prissy gallery-owner Edgar Curtin, Milan's old mob- connected non-friend Victor Gaimari, and (surprise, surprise) April's megadeveloper dad, Chase Delavanheavy hitters all of them, and just the sort of people who wouldn't flinch from having one of the potters who shared Feldman's studio space pushed down the odd elevator shaft. So how can Milan identify the murderer, locate the vase, and keep the panting ceramic collectors from killing each other or him? Actually, it's easier than getting a date for the Indians' opening game. A welcome recovery from the untidy The Lake Effect (1994)a neatly turned mystery with Milan's wit providing a piquant counterpoint to the grim proceedings.