Person Who Doesn't Exist Is Being Clocked In Every Week

a friend of mine is a general manager at a deli/cafe and she has told me countless stories about the owner of the shop being "sketchy" with money, not distributing tips evenly, will make employees jump through hoops to get their paystubs, just generally shady behavior. She has very little access to view pay/timesheets/etc. Well she mentioned to me today there's a person on the clock-in list that "works" 40h every single week that does not exist. She has never interviewed a person by that first name, everyone else is accounted for and this "person" has never been talked about or mentioned. They primarily employ high school/college students and it is a small franchise with a few locations in other cities so it's pretty unlikely that this person is in like an HR or management role doing work outside the building. I told her she should report it but who would she talk to that would actually do something about it? She is also scared she would be fired for digging around in this but this fake person is presumably being given a portion of tips that should be going to other employees, that I would guess the owner is keeping for himself. Any advice would be great.