(WHEATON) A former accountant for a west suburban law firm faces up to 15 years in prison after pleading guilty to stealing more than half a million dollars from the firm over a 6-year period.

Le Anna Kelty, 55, pleaded guilty Friday to one count of theft in excess of $500,000, a Class 1 felony, according to the DuPage County state’s attorney’s office. She facces between 4 and 15 years in prison when she is sentenced Feb. 16 by Judge Robert Miller.

Kelty worked in the accounting department of the Naperville legal firm, and, according to prosecutors, “forged her employers’ signatures and deposited unauthorized checks drawn against the firm’s bank accounts into her personal bank accounts” on several occasions between November 2006 and February 2013.

The thefts were discovered about a year after she left the firm, prosecutors said. “Her scheme unraveled when authorities at the firm discovered discrepancies in their books and, following an internal audit,” contacted law enforcement.

“After years of stealing from a trusting employer, Le Anna Kelty’s deceit and greed finally caught up with her,” state’s attorney Robert Berlin said the statement. “Six years and more than $500,000 later, Ms. Kelty is now looking at a significant amount of time behind bars.”

She remains in custody at the DuPage County Jail on a $150,000 bond.