Armed federal agents wearing hazardous material suits and breathing apparatus entered the West Hills Subdivision home of Paul Kevin Curtis in Corinth, Miss., Thursday evening April 18, 2013. Law enforcement officials blocked off the dwelling after taking Curtis into custody under the suspicion of sending letters covered in ricin to the U.S. President Barack Obama and U.S. Sen. Roger Wicker, R-Miss. (AP Photo/Rogelio V. Solis)

Associated Press
Armed federal agents wearing hazardous material suits and breathing apparatus entered the West Hills Subdivision home of Paul Kevin Curtis in Corinth, Miss., Thursday evening April 18, 2013. Law enforcement officials blocked off the dwelling after taking Curtis into custody under the suspicion of sending letters covered in ricin to the U.S. President Barack Obama and U.S. Sen. Roger Wicker, R-Miss. (AP Photo/Rogelio V. Solis)
Armed federal agents wearing hazardous material suits and breathing apparatus entered the West Hills Subdivision home of Paul Kevin Curtis in Corinth, Miss., Thursday evening April 18, 2013. Law enforcement officials blocked off the dwelling after taking Curtis into custody under the suspicion of sending letters covered in ricin to the U.S. President Barack Obama and U.S. Sen. Roger Wicker, R-Miss. (AP Photo/Rogelio V. Solis)