Restaurant servers depend largely on tips to make their living. But what if a restaurant was skimming off some of that money for itself? That’s one of the allegations in a lawsuit filed last Thursday against the Four Corners Restaurant Group, an action that the plaintiff’s attorney says might result in upwards of $30 million in damages.

The only plaintiff named so far is Erik Luna, a former bartender at Benchmark, but the lawsuit is a class action on behalf of all employees alleging similar treatment—in some cases, over several years. He approached Zimmerman Law Offices with his allegations, and the firm conducted an investigation, speaking with a number of current and former Four Corners employees.

“Everything was consistent, regardless of who we spoke to,” attorney Thomas Zimmerman says.

Filed in Cook County Chancery Court, the suit names as defendants 17 restaurants associated with Four Corners, as well as several holding companies and investment entities. It firstly alleges that restaurants systematically stiffed servers on their tips—that the amount that servers took home at the end of the night was less than what customers gave. It also claims that the receipts each server received, which records their tips, didn’t match their pay stubs at the end of the month; restaurants would allegedly note that servers got more tips than they actually took home. This practice, according to the lawsuit, could serve as a means to avoid paying taxes.

According to Zimmerman, Luna’s pay stubs differed from his receipts to the tune of about $400 a pay period, or approximately $10,000 per year (he worked at Benchmark for seven years, until this past June). “[The servers] are relying on the restaurant to tell them the amount of tips,” Zimmerman says. “They can go onto the payroll website and download pay stubs, but nobody does, and very few of them keep those receipts.”

The lawsuit also accuses all named restaurants of violating minimum wage laws. Four Corners Restaurant Group provided the following statement when reached for comment:

Four Corners has been in business for over 17 years and we pride ourselves on not only the way we treat our customers, but also how we treat our employees. We are confident that when the relevant facts come to light, it will be established that these claims are without merit and based on a misunderstanding. We look forward to proving that.