It's a billion-dollar mystery that could cost the state of South Carolina tens of millions. Excitement and intrigue spread across the state after it was revealed in October the winning ticket of the more than $1.5 billion jackpot was bought at the KC Mart convenience store in the small town of Simpsonville.

"It's good attention and good for the community, you know," KC Mart owner C.J. Patel said at the time.

The announcement was met with celebration. But four months later, no one has claimed the prize, reports CBS News correspondent Anna Werner. It was the second largest lottery jackpot in U.S. history.

"People are still asking about the winner, who it could be," KC Mart employee Himanshi Patel said.

If the prize goes unclaimed by the April 19 deadline, the $1.5 billion will be redistributed to the 44 states – along with D.C. and the U.S. Virgin Islands that take part in the Mega Millions.

The state of South Carolina could lose out on $61 million of income tax revenue from the winner. The biggest Mega Millions jackpot to go unclaimed was a $68 million prize in 2002. The winning ticket was sold in New York.

Included in the fallout would be Simpsonville's now famous KC Mart would not be awarded the $50,000 bonus for selling the winning ticket if the prize goes unclaimed.

"He's hoping that the winner shows up so that the store gets its part," Himanshi Patel said.