Ryan Loskarn, Sen. Lamar Alexander's former chief of staff, is expected to appear in court on Thursday on child pornography charges. Loskarn was arrested on Wednesday afternoon for allegedly possessing and distributing child pornography, shortly after Alexander's office released a statement on the investigation. Alexander's office initially placed Loskarn on administrative leave without pay. But by Wednesday night, Alexander's legislative director David Cleary was the senator's new chief of staff. "The courts will judge Mr. Loskarn’s guilt or innocence," Alexander said, "but under these circumstances, he cannot continue to fulfill his duties as chief of staff of this office." 

As the Associated Press notes, the documents pertaining to the investigation and arrest are still under seal. U.S. Department of Justice spokesman Peter Carr told reporters on Wednesday that Loskarn "was arrested this afternoon by the U.S. Postal Inspection Service based on probable cause for possession and distribution of child pornography charges,” adding that he will remain in custody until Thursday's hearing. Senate sources told Politico that Postal Service investigators searched Loskarn's office computer, in addition to a search at the 35-year-old's home.

Loskarn worked for Alexander's office for two years. He became chief of staff in 2012. The aide is well-known on Capitol Hill, and previously worked as the staff director for the Senate Republican Conference. Before that, Loskarn climbed the congressional staff ladder as an aide to Rep. Wally Herger, a press staffer for the House Rules Committee, and a spokesperson for spokesman for Rep. Marsha Blackburn. Loskarn hasn't yet commented on the charges against him. 

Update: Here's the statement of facts from the investigation into Loskarn, which provides a lot more information on the circumstances leading to his arrest.