They're not sure who it is just yet, but one Chicagoan is about to be $12 million richer.
A Southwest Side gas station sold the winning $12 million ticket for Saturday night's drawing.
The winning numbers were: 06 - 21 - 29 - 36 - 43 and 46, according to the Illinois Lottery. There was one grand prize winner, who purchased their ticket at the Mobil station at 4540 S. Pulaski Rd., according to the Illinois Lottery.
There were 15 people who matched five of six numbers, and they will each receive $1,892.
The next Lotto drawing, with a grand prize of $2 million, is scheduled for Monday night.