Presently there is no way of tracking down a user details who deleted a page. The "Trash' contains only the Page Title and the Operations available on that page (Restore/Purge)

The 'delete page' operation is only available when in 'Edit mode'.

When an user edits a page and then SAVE the page the lastModifier field in the CONTENT table is updated.

DefaultContentEntityManager.saveContentEntity()
...
 if(saveContext != null && !saveContext.doUpdateLastModifier())
            contentEntityObjectDao.saveRaw(obj);
        else
            contentEntityObjectDao.save(obj);

Obviously we can not update the lastModifier field as delete action is not an edit.
Hence we need some other means of mechanism to record the information about the page being deleted, when and by whome.

I propose to create a separate database table which would be used for this purpose.

DELETED_PAGES table
ID     page_title     Date   UserName

This way the Space 'Trash' can show this information.

Further we could implement this on a global level as well. Hence the wiki administrator can obtain a status report about all the pages that were deleted.