A former taekwondo instructor was taken into custody early Saturday by federal authorities in Mississippi, accused of mailing letters containing the poison ricin to the president, a United States senator and a local judge.

The arrest of J. Everett Dutschke, 41, of Tupelo is the second in two weeks in connection with the case. An earlier suspect, an Elvis impersonator named Paul Kevin Curtis, of Corinth, Miss., was released after no evidence was found linking him to the letters. Mr. Curtis’s lawyer had said during a hearing in federal court that Mr. Dutschke appeared to have framed Mr. Curtis.

Deborah Madden, a spokeswoman for the F.B.I. in Jackson, said Mr. Dutschke was arrested at home shortly before 1 a.m. A law enforcement official in Tupelo said his arrest was uneventful.

“He walked out, and they took him into custody,” said Sgt. James Hood of the Tupelo Police Department. “No problem or anything.”