I have a WD Elements USB drive that I had plugged into my NVIDIA Shield to store media on but is now attached to my router.

There are a handful of music and movie files on there that I just can't delete.

I have tried using mapping the drive in Windows but get a permissions error (says files are owned by Linux Root). I've now set up an old laptop with Linux Mint and mounted the drive using cifs but still get a permissions error when I try to delete. SUDO & CHMOD & CHATTR all seem to do nothing for these files.

Searching Stackoverflow has made me think they might have been written in a different filesystem.

How can I find out how these files were written and/or how can I delete them?