Loskarn had been allowed to live with his parents while awaiting trial on charges of possession and attempted distribution of child pornography. He was required to be electronically monitored.
Loskarn had been chief of staff for Alexander, R-Tennessee, for two years before his arrest. Loskarn was fired immediately after his arrest.
"For everyone involved, this is a sad and tragic story from beginning to end," Alexander said in a statement.
David Schertler, a Washington lawyer whose firm represented Loskarn, said the firm did not have an immediate comment on Loskarn's death.
Loskarn was arrested Dec. 11. Prosecutors had been given until Feb.10 to return an indictment. Loskarn's lawyer said in a court filing last month that the two sides planned to try to resolve the case.
According to court documents, law enforcement officials believe that between November 2010 and March 2011, Loskarn made several purchases from a website that was offering child pornography DVDs. Loskarn also was accused of offering child pornography files for download from his home computer.
Court documents say that when law enforcement officials arrived to search his Washington home, one official watched as Loskarn appeared to place an object outside a window. Officials later found a portable hard drive in that location, and a prosecutor said the drive contained at least 200 videos of child pornography.
If convicted, Loskarn had faced up to 10 years on the possession charge and a minimum of five and maximum of 20 years on the distribution charge.
According to Loskarn's biography on his LinkedIn account and in previous communications for Alexander's office, he graduated from Tulane University in 2000 and went to work for retired Republican U.S. Rep. Wally Herger of California as a legal assistant. He later was the communications director for U.S. Rep. Marsha Blackburn, a Tennessee Republican, and eventually became staff director for the Senate Republican Conference.
Loskarn was well versed in Senate procedure and was considered a sharp prognosticator of how debates and standoffs would play out. He was known to share colorful anecdotes and keen observations about body language and mood in the Senate.
Associated Press writers Erik Schelzig in Nashville, Tenn., and Eric Tucker in Washington contributed to this report.