Kholyavskiy v. Achim, 443 F.3d 946 (7th Cir. Apr. 17, 2006) (petitioner should have named the warden of the prison in which he was detained as defendant instead of naming DHS officials, the Secretary of Homeland Security and the Attorney General).
http://caselaw.lp.findlaw.com/data2/circs/7th/052893p.pdf