How to get user id or user name for deleted item

HI all,

I made one programe for unwanted Purchse order deletion. But due to some reason some open po's are deleted due to this program. I corrected this PO's manually. but i want to check from which user id or user name it has been deleted. I check with standard procedure which is go to ME23N->Environment->Item changes. But there is no changes seen in this screen, Is there any other way to see user name or user id?