This item has been updated.

The chief of staff to Sen. Lamar Alexander (R-Tenn.) was arrested Wednesday on charges of possessing and distributing child pornography -- and swiftly fired by the senator.

Jesse Ryan Loskarn, 35, of the District, was arrested at his home Wednesday afternoon by the U.S. Postal Inspection Service and is expected to appear in federal court in Washington on Thursday to face charges, the Justice Department said.

Word of the investigation was first revealed in a statement issued Wednesday morning by Alexander, who said he was "stunned, surprised and disappointed" by the news and would be placing Loskarn on unpaid administrative leave. The news spread quickly across Capitol Hill among Loskarn's colleagues and friends in the close-knit worlds of congressional staffers and Capitol Hill reporters with whom he worked with for years.