Q: Internal memory - presence of unidentifiable movies

Internal memory shows that I have many movies, but I cleared out my files, and it still shows that I have movies. I've already tried to find the source through Disk Inventory X and OmniDiskSweeper, but I don't see any irregularities. I've swept through the iPhoto library, the iMovie library, and other Apple based media forms. I've erased the data from these applications, but I'm continuously finding 40 GB of movie data being shown in the Flash Storage of my internal hard drive. Where else can I find these movies? Does anyone know what causes this occurrence?

Also, does anyone know whether or not when movies are downloaded, Macbooks hold a template or temporary form of these videos, but don't show up as anything but "memory"?