(CNN) -- A 41-year-old Mississippi man accused of sending ricin-laced letters to President Barack Obama and others waived his detention hearing in federal court Thursday and will remain in jail without opportunity for bail, a U.S. District Court in Mississippi said.
Also during James Everett Dutschke's court appearance Thursday, a magistrate ruled that there is probable cause for a federal grand jury to consider the case. The grand jury will now determine what charges Dutschke will face.
On April 22, federal authorities searched a trash receptacle from Dutschke's Tupelo home and found, among other items, different types of yellow paper, address labels and a dust mask. The letters to Obama, Sen. Roger Wicker, R-Mississippi, and Sadie Holland, a judge in Lee County, Mississippi were all on yellow paper.
That same day, according to the affidavit, FBI agents spotted Dutschke leaving his former tae kwon do facility, or dojo, loading items into his car, then placing several items from his window into a public trash can.
According to the affidavit, the items included a coffee grinder, a box with latex gloves, a dust mask and an empty bucket of floor adhesive.
Three subsequent tests of the mask by the National Bioforensic Analysis Center came back positive for ricin, the document states.
Authorities further searched the dojo and tested six other samples, including liquid removed from a drain and swabs taken from inside the building.
At the time, Dutschke told CNN affiliate WMC-TV that he had agreed to the FBI search "to help clear my name."
"I had absolutely nothing to do with those letters," he said.
Yet the affidavit states that laboratory tests showed five of the six samples taken from his dojo tested positive for ricin.
The letters -- all postmarked April 8 -- each had a suspicious substance inside; a Memphis, Tennessee, postmark, and no return address.
They also contained a letter that read, in part: "To see a wrong and not expose it, is to become a silent partner to its continuance."
Earlier, authorities arrested a different man, an Elvis impersonator named Paul Kevin Curtis, accusing him of sending the letters. Authorities eventually released Curtis but not before learning that Curtis knew Dutschke.
The two men knew each other because Dutschke used to work for Curtis' brother at an insurance company.
If inhaled, injected or ingested, less than a pinpoint of ricin can kill a person within 36 to 48 hours due to the failure of the respiratory and circulatory systems. There is no known antidote.
CNN's Greg Botelho and Chuck Johnston contributed to this report.