Federal prosecutors have filed criminal charges against a man arrested in the FBI investigation of letters believed to contain the deadly poison ricin.
The U.S. Department of Justice said on April 18 that Paul Kevin Curtis, 45, is being charged with threatening to harm President Barack Obama and others.
If convicted, he could face up to 15 years in prison.
Authorities said initial tests on letters addressed to the White House, a U.S. senator and a Mississippi justice official indicate the presence of ricin.
Two of the letters were intercepted at offsite mailing facilities; the third one was delivered to a Mississippi state judge.
The FBI is conducting further tests. Curtis was arrested on April 17 at his home in Corinth, in the state of Mississippi and he appeared in court the following day.
His lawyer said Curtis was surprised by his arrest and maintains that he is innocent.
Based on reporting by AP and Reuters