Question : how to audit a file deletion?

How do I set file auditing to show when and who deleted a file.

Answer : how to audit a file deletion?

Enable auditing on the share.
R-click the shared folder -> properties -> advanced -> auditing tab
Add a group or account to audit. Then check successful create file/folder, delete subfolders/files and whatever else you want.

http://support.microsoft.com/kb/814595