A federal judge Tuesday ordered that a Buxton man accused of using his Twitter account to threaten “to kill Jews” with an AR-15 during the High Holy Days be held without bail while the court determines if he can be released without posing a risk to the community.

Brian Dennison, 24, made his first court appearance remotely before U.S. Magistrate Judge John H. Rich III in federal court in Portland. Dennison also had said on Twitter that he was building a pipe bomb, according to court documents.

The judge set a remote probable cause and bail hearing for 11 a.m. Thursday.

He was not asked to enter a plea to the charge of  transmitting threatening interstate communication because he has not yet been indicted by a federal grand jury.

Federal prosecutors have asked that he be held without bail.

Dennison, who was arrested Saturday, allegedly posted the threat shortly after 9 a.m. on Sept. 8, the second day of Rosh Hashanah, the Jewish New Year.

The FBI learned of the threats almost immediately after they were posted, according to a court affidavit. Agents visited the Fogg Road property Dennison shares with his parents and other family members the same day.

Dennison, who rents an apartment over the garage from his parents, refused to speak with the agents and asked them to leave, the affidavit said. Agents did, however, speak to his parents.

“They told us that Brian had been obsessed with Jews for about three years, and that he believed Jews were responsible for all of his problems,” the affidavit said. “They said they had many concerning conversations with Brian regarding Jews.”

The couple also said that their son owns “a few pistols and rifles, including an AR-15-style rifle” but does not keep them locked in a gun safe.

After the agents visited Dennison, he allegedly deleted his tweets and gave three guns to his parents.

Agents returned the next day with a warrant to seize and search Dennison’s cell phone and to examine the guns, according to court documents. They did not find an AR-15 but did find ammunition in Dennison’s apartment that could be used in one.

Agents also found a Nazi eagle, Nazi cards and a sketchbook containing Nazi drawings, according to documents unsealed Tuesday afternoon.

Information about the circumstances surrounding his arrest has not been released.

If convicted, Dennison faces up to five years in prison and a fine of up to $250,000.