A disgruntled former staffer stole data files that contained the personal information of Chicago Public Schools employees, the district said in an email to educators Thursday.

The digital information contained the name, employee ID, phone number, address, date of birth, and prior criminal arrests and state Department of Children and Family Services findings, if applicable, for a number of staff. The district said social security numbers were not contained in the files.

CPS could not immediately provide an estimate of how many employees’ information was compromised. 

According to an email sent to employees, “there is no indication that the information, which was in the individual’s possession for approximately 24 hours, was used or disseminated to anyone in any way. The individual is in police custody, and CPS will work to ensure the individual is prosecuted to the fullest extent of the law.”

A data breach in June exposed the personal information of 3,700 students and families, after a CPS employee accidentally sent an email to selective enrollment applicants and included a link to a spreadsheet with personal information. The private data was active for several hours before CPS noticed. The district apologized for the breach.