Prosecutors in the United States have charged a man suspected of sending poison-laced letters to President Barack Obama and a senator with threatening the life of the president.
Paul Kevin Curtis was arrested by the FBI at his home in Corinth, Mississippi, and was due to appear in court on Friday, AFP reports.
If convicted, he faces up to 15 years in prison and $US50,000 in fines, prosecutors said.
The FBI earlier said the 45-year-old was believed to be responsible for mailing three letters sent through the US Postal Service containing a substance that preliminary tests showed was ricin.
The letters were addressed to President Obama, Republican Senator Roger Wicker of Mississippi and a justice of the peace in the same state, Sadie Holland.
Mr Curtis also wrote about an alleged black market for the illegal sale of human body parts that he thought was being covered up by the government, prosecutors said.
In 2007, Mr Curtis's ex-wife reported to police that her former spouse was extremely delusional, anti-government and believed the government was spying on him with drones.