I searched the help index and went t this lnk: https://confluence.atlassian.com/hipchat/delete-messages-and-files-751698289.html
But I do not see the History link in the left nav as suggested in the above doc
It looks like that documentation might be a little out of date about the location of the history search. Roughly the same procedure should still work, using the history search in the upper right (the box next to your avatar).
Try the following.
If you have any trouble doing this from your desktop client, the same procedure works from the web interface of HipChat.
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