(RNN) - A suspect has been arrested in connection to the possibly ricin-laced letters that were sent to President Barack Obama and Sen. Roger Wicker, R-MS.
Paul Kevin Curtis, 45, of Corinth, MS was taken into custody by federal authorities.
The FBI says special agents arrested Curtis at his home on Wednesday.
Corinth is near the Tennessee-Mississippi state border and nearly 98 miles east of Memphis.
The letters that were sent to Obama and Sen. 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."
The letters were postmarked in nearby Memphis, TN. Tupelo's mail is routed through Memphis, according to the Clarion Ledger.
Curtis has been under investigation for some time because he had been sending letters to Wicker for some time, CNN reported.
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.
Wednesday also came with other suspicious activity at various senators' offices and at the Capitol.
According to the Associated Press, Capitol police spokeswoman Makema Turner said late Wednesday the three packages in the Capitol complex turned out to be safe. Turner also said the man who was stopped in connection with the packages was still being questioned.
CNN reported that authorities called the suspicious mail sent to Arizona Sen. Jeff Flake's office earlier Wednesday was a false alarm, while the suspicious mail sent to the Saginaw, MI offices of Sen. Carl Levin are still being investigated.
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.