(RNN) - A suspect who the FBI says sent letters that tested positive for ricin to President Barack Obama and Sen. Roger Wicker, R-MS, has been arrested.
FBI special agents took Paul Kevin Curtis, 45, of Corinth, MS, into custody at his home on Wednesday.
Corinth is near the Tennessee-Mississippi state border and nearly 98 miles east of Memphis. The letters were postmarked in nearby Memphis, TN.
The letters that were sent to Obama and Wicker were reported to have said, "To see a wrong and not expose it, is to become a silent partner to its continuance."
They were both signed, "I am KC and I approve this message."
Field tests showed that the letters tested positive for ricin. However, those tests are not conclusive, and lab test results are expected within the coming days.
The letters never reached Obama and Wicker. They were intercepted at a processing facility.
In a press conference Wednesday night, officials said the suspect will not be formally charged until the finalized test on the chemical substance is proved to be ricin.
They would not say where Curtis is being held.
Curtis has been under investigation because he had been sending letters to Wicker for some time, CNN reported.
Wednesday also came with other suspicious activity at various senators' offices and at the Capitol.
According to the Associated Press, suspicious packages sent to three Senators' offices on Wednesday turned out to be benign, and the person detained and questioned was released.
CNN reported that authorities called the suspicious mail sent to Arizona Sen. Jeff Flake's office earlier Wednesday a false alarm, while the suspicious mail sent to the Saginaw, MI, offices of Sen. Carl Levin are still being investigated. A package sent to Sen. John Cornyn's office in Dallas was also not dangerous.
Ricin is a poison that is present in castor beans, according the New York State Department of Health. It is part of the waste that is produced during the production of castor oil and as such, is one of the most easily produced plant toxins.
The chemical is extremely deadly, and an amount as small as a pinhead, about 500 micrograms, can be enough to kill.
Copyright 2013 Raycom News Network. All rights reserved.