The House Oversight Committee under Darrell Issa is slated to hear testimony today on another Obama administration cover-up. ... A unit run by President Barack Obama's political staff inside the Environmental Protection Agency operates illegally as a "rogue law enforcement agency" that has blocked independent investigations by the EPA's inspector general for years, a top investigator told Congress. The assistant EPA inspector general for investigations, Patrick Sullivan, was expected to testify Wednesday before a House oversight committee ... The office of about 10 employees is overseen by EPA Administrator Gina McCarthy's office, and the inspector general's office is accusing it...