Admins can see a list of deleted user posts at /u/username/deleted-posts. The expectation is that a listed post will include the title of the topic it belongs to (linking to the relevant post), as well as a link to the category that holds the topic. I’m finding that if the topic post (OP) of the associated topic is deleted, that deleted post and any deleted replies will be listed without including a title and category link. The code suggests that the title and category would be shown in all cases.
An example shows how the topic titles are displayed when the OP has been deleted, and when the OP still exists:
