We recently had a need to find who removed a user from a group. Under Security, User Management, there is a report for Users removed from group in the last 30 days. However, the "who" in this report is the person who made the change - not the member of the group. The only way we found to answer the query was to manually go through each change.
Is there a way to do a search for the Group name or the Member of the group?
What you are looking for is in the "What" tab. Since we don't know the who yet, we can put the user that was removed in the What tab and find everything that happened to the user during that timeframe. If there is a whole bunch of things, we can further filter it by the the kind of action that was done. Here is a screenshot where I did a similar search: