The man accused of mailing poison-laced letters to elected officials such as President Barack Obama and Sen. Roger Wicker, R-Miss., pleaded guilty on Friday, Mississippi media outlets reported.
James Everett Dutschke, of Tupelo, Miss., admitted to making ricin and sending the letters, which rocked the Capitol Hill community in April.
Dutschke, 42, who has been in jail since April, was charged in November with trying to get someone to send more letters containing the deadly substance on his behalf. He initially denied responsibility for the letters and is also accused of trying to frame an Elvis impersonator named Paul Kevin Curtis for the attacks. Curtis, whom Wicker once hired to entertain at a party, was arrested but all charges were later dropped.
The most serious charge, production of a biological weapon, carries a potential life sentence.
A reporter covering the Oxford, Miss., hearing for WREG reported that Dutschke was in tears during his appearance.
There is no sentencing date yet.