The U.S. Department of Justice is pursuing an unusual denaturalization case against a former Marine for sex crimes committed after obtaining citizenship, representing a departure from the government's traditional approach to citizenship revocation.

Historically, federal authorities have typically sought to revoke naturalized citizenship based on misconduct or false statements made during the citizenship application process itself. The current case marks a shift toward targeting crimes committed after naturalization was completed.

The case comes as the Department of Homeland Security has established a new unit focused on reviewing the cases of thousands of permanent residents who hold green cards. This specialized unit is tasked with re-examining the backgrounds and eligibility of immigrants with permanent residency status.

Denaturalization proceedings, while rare, have been used in cases involving war crimes, terrorism, or fraud in the naturalization process. The expansion to include post-naturalization criminal conduct could signal a broader interpretation of grounds for citizenship revocation.

The new DHS unit represents part of what officials describe as an enhanced "removal apparatus" designed to identify individuals whose immigration status may be subject to review. The unit's formation indicates increased federal scrutiny of both naturalized citizens and permanent residents.