Hello Richa,
Have you also tried SWI2_ADM2?
ADM1 will show items without agent. But if your expected items have an assignment, ADM1 will not report them, even if the user does not exist (this may be a valid case). ADM2 is for the scenario where a user doesn't exist.
Failing that, if you know what the items are, you can always look in table SWWUSERWI who has it.
Regards,
Mike