Hi,
In the Azure Activity log you can see a log of when resources were deleted, which user deleted them, etc. For example, if someone deletes a Resource Group, the log will have "Delete Resource Group" for operation name and the name of the resource group will be part of the Resource.
To view Azure Activity log in the portal, navigate to your subscription and then click on Activity log blade. Sample screenshot below:
Please click Accept Answer if the above was helpful.
Thanks.
-TP