To establish context when you search for a file start by indicating the Container/or MPUB to search in:
The Container drop down list represents the Disaster Containers you are a member of plus MPUB.
If MPUB is selected, you can further specify Country and Agency limitations. The standard values are picking out the files created by your own agency.
If you want to see all the national missing persons, switch agency to [All]. It has to be noted that "national missing persons" refers to the files that your country owns, and not the files related to nationals of your country.