delete by?

“Trashed” and “Permanently deleted” are two differently things.

Trashed posts get assigned a post status of “trash” and then only appear in the “Trash” section of the page/post section of the admin area. These posts still exist, as such, it is possible for the plugin to keep track of and report who trashed the post.

Permanently deleted posts, as you noted, are completely removed. This plugin does not track who deleted those posts.