Department of Homeland Security Secretary Kristi Noem reported Monday that her agency has identified people who have been leaking the times and locations of Immigration and Customs Enforcement raids.

Noem said the department was using polygraph tests to find the individuals responsible, along with reviewing emails of suspects, and auditing their communications.

Homeland Security Secretary Kristi Noem announced she had fired the employees in her department who were leaking information to the press. This comes as activists against Immigration and Customs Enforcement have engaged in a variety of protests.