Sen. Lamar Alexander, R-Tenn., announced he has suspended his chief of staff, Ryan Loskarn, after learning that the staffer's home was being searched by law enforcement officials "regarding allegations involving child pornography."

The senator made the announcement on his official website:

"I was just informed by the United States Senate legal counsel’s office that law enforcement agents are conducting a search of the personal residence of Ryan Loskarn, the chief of staff of my Washington, D.C., office regarding allegations involving child pornography. I am stunned, surprised and disappointed by what I have learned. Based on this information, I immediately placed Mr. Loskarn on administrative leave without pay. The office is fully cooperating with the investigation."

Loskarn took over as Alexander’s chief of staff in January 2012. Prior to that, he was the staff director of the Senate Republican Conference and a spokesman for Rep. Marsha Blackburn, R-Tenn.

Loskarn was described by Roll Call as "one of the Senate GOP's top strategists and aides, and he has been a fixture in the House and Senate for most of the past decade." He worked at the Senate Republican Conference while Alexander was chairman and under his predecessor, Sen. Jon Kyl, R-Ariz. Loskarn also worked for Reps. Wally Herger, R-Calif., and Marsha Blackburn, R-Tenn., and at the House Rules Committee.

“I am fortunate that Ryan Loskarn is willing to transfer his considerable skills from leading the Republican Conference to leading my Senate staff,” Alexander told Roll Call for a November 16, 2011 story.

Alexander is the ranking Republican on the Senate Health, Education, Labor and Pensions Committee.

UPDATE: Loskarn was arrested Wednesday afternoon by U.S. postal inspectors on charges of possession and distribution of child pornography, the Justice Department announced. He is set to be arraigned Thursday morning in federal court.

“The courts will judge Mr. Loskarn’s guilt or innocence, but under these circumstances, he cannot continue to fulfill his duties as chief of staff of this office. Therefore, as of today, I have removed him from the payroll,” Alexander said Wednesday afternoon.