In order to check whether a particular member was a part of group or not you need to navigate to that User profile. Right click on the form header and then click on History-->List as shown below:
If you are not able to see the List option highlighted above in User profile then you need to Turn the Auditing for the user Table as per the steps mentioned below:
1) Navigate to "Dictionary" under System Definition.
2) Search Table = "sys_user" and scroll down to find the below entry highlighted in the screenshot:
3)Open the Record highlighted above and click on the Auditing check box to mark it as True as shown below:
Once the Auditing has been turned on follow the below steps to check on your requirement:
Post click on the List scroll down to the "Audit History" tab and check for the Label/Type as "relation" as shown below:
Open the particular Relation record where you can find the name of the Group from which the user was removed as shown below:
On the below right side, you could see the User, User ID and User Name of the one who updated. Try it out in the test environment. This would have the backed dated values as well.
You could turn of the audit once completed. I got no idea to check without the use of audit table.
Hope this helps. Mark the answer as correct/helpful based on impact.
