Forty-seven-year-old John Philip Barker pleaded guilty to one count of mailing a threatening communication. The U.S. attorney's office said today that Barker admitted that on June 21, 2008, he mailed a letter to the IRS in Austin, Texas. The letter said: ``YOU HAVE BEEN EXPOSED TO ANTRAX DIE!''
Authorities determined the letter did not contain anthrax.
Sentencing is set for Aug. 10. Barker faces up to five years in prison and a fine up to $250,000.