A grand jury will decide whether to charge a Mississippi man and one-time Wayne Newton impersonator with sending ricin-laced letters last month to President Obama, a U.S. senator and a local judge.

J. Everett Dutschke, 41, will remain in jail after a judge in Oxford, Miss., determined Thursday that investigators have produced enough evidence to send the case to a grand jury.

The ricin-laced letters were discovered at mail screening facilities outside Washington that are used to ensure letters and packages are safe before delivering them to the White House and Capitol.

Sen. Roger Wicker, R-Miss., was the intended recipient of one of the letters.

Off-site screening was implemented years ago after letters laced with anthrax were mailed to the U.S. Senate shortly after the Sept. 11, 2001, terrorist attacks.

The culprit in the anthrax case was never found, but the FBI appears to have accumulated extensive evidence in the ricin incident to charge Dutschke.

Dutschke is the second man arrested in the case, which has taken bizarre twists and turns.

The FBI originally suspected Paul Kevin Curtis, an Elvis Presley impersonator from Tupelo, Miss., of sending the letters and took him into custody only to release him a week later after digging through his house for evidence.

Dutschke is believed to have been involved in a long-standing feud with Curtis and signed the letters "KC" to shift suspicion to Curtis.

Curtis was released and is no longer considered a suspect. He said he believes he was framed by Dutschke.

An affidavit released this week shows Dutschke, also of Tupelo, may have bought the ingredients and equipment needed to make ricin, a derivative of the castor bean than can in some cases kill those who ingest even very small amounts.

An FBI surveillance team saw Dutschke dump a coffee grinder, gloves, a dust mask and a bucket into a garbage can. Agents retrieved the items and found that they tested positive for ricin. Ricin traces also turned up at Taekwondo Plus, where Dutschke once worked as a martial arts instructor.

Law enforcement officials say Dutschke purchased 50 red castor beans in November on eBay and another 50 beans in December.

According to FBI special agent Stephen E. Thomason, "the number of castor beans ordered is more than sufficient to extract the quantity of ricin found in the three letters."

Thomason appeared on the stand in federal court Thursday, outlining how the FBI came to determine Dutschke was their suspect. According to local reports about his testimony, Thomason cited the affidavit, adding that the FBI heard from witnesses that Dutschke would often begin his martial arts classes with "rants against the government."

Thomason, local reports said, told the judge that the FBI is searching a third location and that Dutschke appears to have purchased a third shipment of castor beans.

On his Twitter page, Dutschke, who in 2007 ran for the Mississippi state legislature, identifies himself as "A Philosopher trapped in the body of an Insurance Agent."