When a file or folder get deleted on major file systems it's only the filename that gets affected by this action. In the most primitive case it loses its first character, and the disk space where that file resided is marked as available for new data.
This ensures the fastest deletion possible. It also results in the disk sectors still storing the deleted data. Disk Drill (former Pandora free data recovery) can still recover it! We offer the best of breed recovery algorithms to scavenge that data for you.