This is found in the review queue. So if you go to /review on your site, you will be able to filter the results like so:
So for example above I selected ‘all reviewed’ and this (below) is the last reviewed item. Of course you can filter by username, date etc.
Another way to find out is by going to a topic, clicking the topic actions 
and pressing ‘Moderation History’ this will pull up any relevant moderator actions in that specific topic.