Paul Kevin Curtis, the 45-year-old Mississippian charged with sending lethal poison in letters to President Obama and Sen. Roger WickerRoger Frederick WickerGOP senators introduce bill to prevent family separations at border Overnight Defense: States pull National Guard troops over family separation policy | Senators question pick for Afghan commander | US leaves UN Human Rights Council Senators question Afghanistan commander nominee on turning around 17-year war MORE (R-Miss.), was personally acquainted with Wicker when Curtis's activities were less threatening.

Wicker told reporters he knew Curtis from “social events” when he was in the House and represented Curtis’s district.

Wicker laughed when asked what he remembered about Curtis.

"Well, he’s an entertainer. He’s an Elvis impersonator," Wicker said. "He entertained at a party that my wife and I went to. ... My impression is that about that time he had some mental issues, and was perhaps not as stable. A number of couples threw the party ... and we kicked in [money to pay him] I’m sure."

Locals in Corinth, Miss., expressed shock at the news of Curtis's arrest. Ricky Curtis, who claims to be Kevin Curtis's cousin, told CBS News that Kevin Curtis impersonated Elvis, among other musical performers. 

Curtis, according to authorities, is now charged with sending mail "containing threats to take the life of or to inflict bodily harm upon the President of the United States" and also sending mail "containing a threat to injure the person of others." He faces up to 15 years in prison, authorities said.