Federal prosecutors say a cashier at a Pittsburgh monuments and engraving firm stole at least $9.5 million from the company during the 16 years she worked there.

The charges filed Wednesday against 55-year-old Cynthia Mills include tax evasion and money laundering. Her attorney says he plans to comment on the charges later Wednesday.

A spokesman for Matthews International Corp. says the company has been cooperating with federal authorities on the theft since 2015.

The company said in a financial report that year that a former employee was suspected of stealing $14 million, and prosecutors filed petitions to seize a $645,000 yacht, two Mercedes automobiles and a Ford Focus believed bought with the money.

Prosecutors didn't immediately explain the discrepancy in the alleged theft amount.