The California-based Sutter Health East Bay region has notified 4,500 patients that their personal information was taken from the hospital during an unrelated criminal investigation.

Authorities only found out about because of a drug bust in Oakland in May, according to KTVU.com.

The information may have originated from Sutter Health’s Alta Bates Summit, Sutter Delta or Eden medical centers, and may have included a patient’s name, Social Security number, date of birth, gender, address, zip code, home phone number, marital status, name of employer and work phone number, according to Sutter Health East Bay officials.

The Sutter Health East Bay Region covers Alameda and Contra Costa counties with three medical centers spread across six campuses, plus a medical foundation of physicians at care centers located throughout the East Bay Region.

While it is presently unclear where the information originated, Sutter Health East Bay has notified the patients whose information was potentially involved and are offering them free credit monitoring services.

In 2011, a breach at Sutter Health involving the theft of a company-issued password-protected unencrypted desktop computer led to a billion dollar lawsuit.