Hi Pinaki,
If your search does not retrieves the user when searching from CMC
try the below steps if you remember the account name of the user.
open query builder (http://server:port/AdminTools) and run the below query
select * from CI_SYSTEMOBJECTS where SI_NAME = '<account name of user>'
If this returns result that means the object still exists in CMS DB,
Regards,
RVS