Federal agents arrested a Mississippi martial arts instructor on Saturday after his home and a former business were searched as part of an investigation into ricin-laced letters sent to President Barack Obama and two other public officials.
Everett Dutschke, 41, was taken into custody by U.S. marshals at his Tupelo home early Saturday morning without incident, the city's police chief, Tony Carleton, told Reuters.
It was not immediately known if Dutschke has been charged in the ricin investigation.
Agents from the FBI and the U.S. Capitol Police, as well as members of an anti-terrorist response team from the Mississippi National Guard, had searched Dutschke's home on Tuesday and Wednesday, as well as the premises of a former martial arts studio Dutschke ran in the city.
Agents had Dutschke's home under surveillance on Friday afternoon and evening and moved to arrest him about 1 a.m. CDT (0600 GMT).
U.S. prosecutors dropped charges on Tuesday against another Mississippi man, Elvis impersonator Paul Kevin Curtis, who was released from jail after a search of his home in nearby Corinth revealed no incriminating evidence.
Letters addressed to Senator Roger Wicker, a Mississippi Republican, and Democratic President Barack Obama were retrieved last week at off-site mail facilities before reaching their intended victims. The discovery added another layer of anxiety as authorities dealt with bombings at the Boston Marathon.
Ricin, which is made from castor beans, can be deadly to humans and is considered a potential terror weapon, particularly if refined into an aerosol form.