You do have a running history of this PC, you know what should be there. Sometimes, using more PC utilities finds things not known or they had been meant not in some narifous action but present in some benign way. Have you looked into that partition? Also, understand some hidden partitions are also known as "OEM recovery/restore partition" but you lacked all details of your father's PC.
I was going to just delete it but then I thought more investigation would make snese. I have no idea how this partition was created, but I know my Father couldn't have done it. This sounds like some sort of virus. Any help would be greatly appreciated.