Batman Gotham Knights #72 (2000)

Written by A.J. Lieberman
Art by Al Barrionuevo & Bit
Cover by Claudio Castellini
In a long-forgotten summer home that belonged to Thomas and Martha Wayne, a body turns up that will lead Bruce Wayne to a part of his parents' past he never imagined existed, forcing him to ask himself if his parents' marriage was nothing but a sham!