I assume this file belongs to a specific Client/Subclient and would be backed up to Disk then Aux copied to Tape.
You can narrow down your search by reviewing the period the file was backed up (from the subclient levle), find all the associated Backups (During that time period) and right click (View Media). This will show you the Disk Media as well as the Tape Media those Backups are written to.
This should give you a pretty accurate list of Tape Media which should contain that specific Backup and File. (Note - these tape media will mostly contain other Backup jobs)