ST. PAUL — A federal judge presiding over the case of an alleged bomb-maker from Montevideo has ruled that prosecutors can’t use some of the defendant’s statements at trial because FBI agents went too far in their initial questioning of the suspect.

Buford “Bucky” Rogers was arrested in May in what the FBI called “a terror plot.” He was indicted on four felony charges, including three counts of possessing homemade bombs. He is scheduled to go to trial Jan. 13.

FBI agents had questioned Rogers before advising him of his right to remain silent. While that’s allowed in cases where there’s an imminent threat to public safety, U.S. District Judge Ann Montgomery said Friday the agents’ line of questioning was unrelated to public safety.

Agents asked Rogers, who turned 25 on Friday, about guns he allegedly had in his possession despite a previous felony conviction for burglary that barred him from owning firearms. The questioning came after agents had already seized the weapons.

“This line of questioning cannot reasonably be found to be motivated by exigent circumstance or the public safety,” Montgomery wrote. “… The firearms had been secured and all persons found at the search site had been detained.”

Rogers was arrested May 3, the same day authorities said they found two Molotov cocktails, a pipe bomb and two black powder-and-nails devices when they raided his parents’ mobile home.

The government accuses Rogers of being part of a tiny militia plotting to blow up Montevideo’s police station and raid a National Guard armory.

However, Rogers was not charged with terrorism-related offenses. Rogers’ public defender has said his client wanted to protect the country from a violent Mexican drug cartel he believed had moved into the area.

Agents had questioned Rogers for about 40 minutes before advising him he had a right to remain silent and a right to a lawyer. Rogers waived the rights and kept talking.