Elvis impersonator who 'sent deadly ricin letter to Obama and GOP senator' charged with threatening the president and faces other federal charges
Paul Kevin Curtis, 45, arrested on Wednesday evening at his apartment in Corinth, Mississippi
Charged Thursday with threatening the president and will appear in federal court Thursday
FBI believe he is responsible for mailing three letters laced with ricin to the President, Senator Roger Wicker from Mississippi and a Mississippi judge
He is professional celebrity impersonator who performs under the stage name of KC
Curtis said to be behind online rants about a body parts conspiracy - a Facebook page says 'I'm on the hidden front lines of a secret war'
Envelopes to Obama and Wicker both signed 'I am KC and I approve this message' were intercepted at Maryland post office on Tuesday
Charges have not yet been filed, pending final tests on the substance found on the letters
