The law enforcement arm of the U.S. Postal Service is cooperating with federal immigration officials to locate people suspected of being in the country illegally, according to documents. Via the Washington Post:

The U.S. Postal Inspection Service, a little-known police and investigative force for the mail agency, recently joined a Department of Homeland Security task force geared toward finding, detaining and deporting undocumented immigrants, said the people, who spoke on the condition of anonymity for fear of professional reprisals.

Immigration officials are seeking photographs of the outside of envelopes and packages — an Inspection Service program known as “mail covers” — and access to the postal investigation agency’s broad surveillance systems, including Postal Service online account data, package- and mail-tracking information, credit card data and financial material and IP addresses, the people said.

The postal collaboration is a significant escalation in the Trump administration’s immigration crackdown. Homeland Security officials have previously partnered with tax, housing and public health authorities. But the involvement of the Postal Inspection Service, the nation’s oldest law enforcement agency, means efforts to pursue undocumented immigrants have expanded into one of the most mundane government activities: delivering the mail.