A search warrant for CAG enterprise's CEO's house is released without any evidence.
It makes little sense for Holmes to submerge the Stanley cup in a bathtub to determine its density. That experiment is very inaccurate even with much smaller objects which can be submerged in a beaker. It would be much easier for Holmes to determine the cup material by removing a tiny sample and have one of his "Irregulars" analyze it with spectrometers in a chem lab.