After asking here what can cause an answer to get deleted without any information who deleted it any why, I learned that when 6 users vote "Recommend Deletion" in the low quality review process, the post is indeed deleted but it does not add actual delete "event" to the post revisions.
Can you please add some indication the post is deleted in the revisions list?
I suggest something like:
deleted via low quality review
Where the "low quality review" is a link to the relevant review item.