A hacker has exposed a massive trove of data revealing the inner workings of the U.S. Department of Homeland Security (DHS).

Records identifying more than 41,000 DHS employees and contractors were published online Wednesday by the nonprofit Distributed Denial of Secrets (DDoSecrets), which specializes in publishing and archiving leaked datasets.

DDoSecrets says the data came from an Okta single sign-on system used by DHS and includes employee names, office locations, contact information, job titles, and assignments. The records also reportedly reveal the software employees may have access to.

The data was allegedly obtained by a hacktivist group known as the Department of Peace, who provided copies to DDoSecrets and independent journalist maia arson crimew .

“On July 17th, Markwayne Mullin said he was ‘turning up the heat.’ This is what happens to ICE when you do that,” said a spokesperson for the Department of Peace in a statement published on DDoSecrets’ website.

Crimew also created an online search…