Space Occupied By Other Files And Folders On Hard Drive
Have you attempted to empty the trash after removing the VM? Alternately, I believe that VirtualBox keeps its data at "~/VirtualBox VMs". Removing that folder may help you to reclaim drive space.

Here's more info on TimeMachine's local snapshots. If you'd like to disable that feature, you can use these commands to perform that action:

sudo tmutil disablelocal


Here's how you can re-enable local snapshots:

sudo tmutil enablelocal


Here's how to take a snapshot:

tmutil snapshot