Elizabeth Paige Laurie, the granddaughter of Wal-Mart co-founder Bud Walton, has returned her diploma, nullifying her degree from the University of Southern California.

The move comes a year after her former college roommate alleged she was paid $20,000 to do Paige Laurie's homework.

Elena Martinez told ABC's

In a statement dated September 30, but not widely distributed until the school newspaper wrote about it late last week, the school says, "Paige Laurie voluntarily has surrendered her degree and returned her diploma to the university. She is not a graduate of USC. This concludes the university's review of the allegations concerning Ms. Laurie."

Laurie had been given a bachelor's degree by the USC Annenberg School for Communication in May 2004.