Have you used the computer's search to look for files? For LW versions 4.12.6 & earlier, files are deleted without being sent to the recycle bin, if they're deleted from LW's library. The 4.13.0 beta will send files to the recycle bin.

Check the sticky below for file recovery advice, some people have has success with the Restoration program.
Deleting files from LW library - Don't!! File recovery advice