Files not deleting

[Kingofdust]

So here is my problem: I went to delete a large quantity of data about 30 gigs in fact but I didn't know about the hold option trick so the trash just made the noise and the files disappeared for anywhere but the hard drive still reads full. where do I find these files to properly delete them once and for all, trash has been emptied several times properly to confirm that it is deleting while holding option, but the initial 30 gigs is in limbo.