The founder of a Philadelphia cheesesteak restaurant and one of his sons have pleaded guilty in a federal tax fraud case alleging the hiding of nearly $8 million in sales over the course of a decade.

The Philadelphia Inquirer reports that 83-year-old Anthony Lucidonio Sr. and 55-year-old Nicholas Lucidonio, two owners of the well-known cheesesteak and sandwich shop Tony Luke’s, pleaded guilty Monday to conspiring to defraud the U.S. government.

The two are to be sentenced later this year.

They said in a statement that they “accept full responsibility," have cooperated with authorities and “look forward to putting this matter behind them.”