A Northwestern Memorial Hospital employee has been charged with identity theft after she allegedly used personal information from hospital patients to pay her bills, according to a report from the Chicago Tribune.

Shatina Golden, 35, of Matteson, Ill. has been charged with aggravated identity theft and identity theft, after working at the hospital for the last four years, according to the state’s attorney’s office.

Police began investigating her after officials spotted “suspicious credit card activity,” such as payments for her home water bill. Police said they identified the owners of the credit cards Golden used to pay her bills, and they learned from credit companies that all of the cards had been used at a laboratory at Northwestern Memorial.

Matteson found credit card numbers, birth dates and Social Security numbers from more than 50 patients during a search of Golden’s home, the article says.

If convicted, she faces up to seven years in prison.