user search via tag

I want to modify the default "user search via tag" so that it can search in a customized way. Now I go to mod/members/index.php and trying to study the code at this file.  I can find "$sidebar = elgg_view("members/search");" statement. Is this the searching function? Where can I find the file which contains the coding? If I want to include "about me" as a tag search here, is this the right file which I need to modify? If not, can anyone please let me know where I can make modification? Thanks.