Why didn't <PERSON> ask the house elves to search for the Chamber of Secrets?
<PERSON>, presumably knowing that house elves have powers that wizards do not, (such as being able to apparate within Hogwarts), could have asked them to help search for the chamber of secrets, since he knew it existed and <PERSON> had opened it, though he could not find it. He also knew that <PERSON> died when it was opened, so I expect that he asked her about it. If she told him the same that she told <PERSON> (that she was in the bathroom, heard a boy's voice and died instantly after seeing a pair of great big yellow eyes), he would definitely have guessed that the bathroom had a lot to do with the chamber. The tap for the sink in front of her toilet had a copper snake engraved, and she said that the tap never worked. 773
This is more than enough for <PERSON> to surely want to investigate the tap, so even if he could not sense the concealed entrance (though he certainly could by the time he entered the locket cave), he would know where to start searching. So why did he not get all the help he could? He was certainly not ignorant of the house elves and could understand them quite well (witness how he knew <PERSON>'s involvement in <PERSON>'s case).
<PERSON>'s razor tells me that it was a plot hole. But is there a good possible explanation consistent with the rest of the story? If he never asked <PERSON>, why not? If he asked, why did he not find the tap and then the entrance? If he found the entrance but could not open it, why did he not ask the house elves to help? (And their apparation abilities would be useful here.) <PERSON>'s phoenix Fawkes was also able to apparate into the chamber of secrets when <PERSON> mentioned <PERSON> to <PERSON> (he appeared atop a pillar). There were just too many ways <PERSON> could have gotten into the chamber once he found the entrance, so is there evidence for why the house elves could not have helped him find it? 573