(CNN) -- A New York man was arrested and charged Friday by federal prosecutors with threatening to assault and murder two US senators in retaliation for their support of Justice Brett Kavanaugh's confirmation to the Supreme Court.
The man, Ronald DeRisi, left more than 10 threatening and "expletive-laced" voicemails for the two senators beginning September 27, according to the complaint unsealed Friday by prosecutors in the US Attorney's Office for the Eastern District of New York.
In one message, DeRisi said he had a "present" for one of the senators, the complaint says, adding: "It's a nine millimeter. Side of your f---ing skull, you scumbag motherf---er." He finished the call by saying, "Yeah, Kavanaugh -- I don't think so."
The two senators are not identified by name in the complaint. The date DeRisi allegedly began leaving the messages is the same day both Kavanaugh and Christine Blasey Ford, a professor who accused Kavanaugh of sexual assault when they were in high school, testified before the Senate Judiciary Committee.
Kavanaugh denied those allegations and was confirmed earlier this month.
"Representative democracy cannot work if elected officials are threatened with death for simply doing their job," US Attorney Richard Donoghue said in a statement.
On Friday, a frail DeRisi was wheeled into court wearing a blue T-shirt and jeans. DeRisi made small whimpers of pain as he heard Assistant US Attorney Justina Geraci lay out the case.
Geraci said DeRisi went to great lengths to hide his identity by using burner phones, a fake name, notes to remind himself what that fake name was and a separate credit card to replenish the phone that he hid in his car from his wife.
They were measures that show "a level of criminal intent," Geraci said.
"He's taken steps to hide what he's done from both his victims and his wife," Gerasi added
DeRisi is also alleged to have made the calls to the offices of both senators and the cellphone of one of them, Geraci said.
"He wanted them to know he knew where they were and how to reach them," Geraci said.
DeRisi's attorney, Peter Brill, said that his client posed no flight risk and was not a threat. He tried to explain away DeRisi's actions by saying his brain had been atrophying.
"There is no doubt that this is something that he should not have been doing. But is he a flight risk? No. Is he dangerous? No," Brill said, later clarifying that he meant physically dangerous because DeRisi is so frail.
"He's not a violent person. He's a belligerent person," Brill said. "This is an ongoing neurological problem that has manifested itself in this way."
DeRisi had no memory of making the calls and when he was told of the allegations, he only replied "Oh, my God," according to Brill.
"Mr. DeRisi is just an angry, sick old man," Brill said. "He's not a threat to anybody other than obviously the allegations here, that he made really upsetting phone calls. We feel terrible that that happened but he's not a physical threat to anybody."
DeRisi was remanded back into custody, where he will be given a psychiatric evaluation.