745 ILCS 22/5: Definition.

As used in this Act, "federal law enforcement officer" means any officer, agent, or employee of the federal government commissioned by federal statute to make arrests for violations of federal criminal laws, including but not limited to, all criminal investigators of:

(a) The United States Department of Justice, the Federal Bureau of Investigation, the Drug Enforcement Administration, and all United States Marshals or Deputy United States Marshals whose duties involve the enforcement of federal criminal laws;

(a-5) The United States Department of Homeland Security, United States Citizenship and Immigration Services, United States Coast Guard, United States Customs and Border Protection, and United States Immigration and Customs Enforcement;

(b) The United States Department of the Treasury, the Alcohol and Tobacco Tax and Trade Bureau, and the United States Secret Service;

(c) The United States Internal Revenue Service;

(d) The United States General Services Administration;

(e) The United States Postal Service;

(f) (Blank); and

(g) The United States Department of Defense.