customer can't find emails moved at the root level-IPM tree

Customer did a search and able to find it in ipm_subtree folder. Customer had moved messages to the root of the mailbox(ipm tree). To find these messages:
You can find these messages by doing a “find” at the root level.
Right-click mailbox-username in the left pane and chose “Advanced Find” and then the “advanced” tab
Chose the “field” dropdown and select “all mail fields” and then “in folder”
Make the value “IPM_SUBTREE” and click “find now”