A former Hopkins mayoral candidate who used racist rhetoric during his campaign last year is now awaiting trial after allegedly threatening to kill a federal judge.

Robert Phillip Ivers, 65, was arrested after telling two attorneys in February, “You don’t know the fifty different ways I plan to kill” the judge after she ruled in favor of an insurance company he sued.

The judge is not named in the charges, but Ivers had repeatedly lashed out against U.S. District Judge Wilhelmina Wright while he sued to recoup policy proceeds from a life insurance company. Speaking by phone in February with two attorneys who later reported his statements, Ivers allegedly said Wright “stacked the deck against me to make sure I lost the case” and that she “stole my life.”

A federal grand jury on Tuesday returned a superseding indictment against Ivers, who has been held in Sherburne County jail since his April arrest and is scheduled to stand trial on Sept. 10. Ivers is facing charges of threatening to murder a federal judge and interstate transmission of a threat for making the statement over the phone while in North Dakota.

While running for mayor of Hopkins last fall, Ivers sparked outrage during a candidate forum when he referred to people as “ethnics” and “coloreds” and said a proposed light-rail line into town would bring “riff raff and trash from Minneapolis.” Ivers won just 9 percent of the vote and overwhelmingly lost an earlier bid for mayor in 2015.

Ivers’ defense team and the U.S. Attorney’s Office both declined to comment before trial. However, through recent court filings, prosecutors have said they intend to offer evidence of previous threatening statements made against other judges and court officials in recent years. Last year, a Hennepin County jury convicted Ivers of stalking by phone and acquitted him of a terroristic threats charge in connection with a string of messages left for a state court judge that included, “I’m going to make sure you feel some [expletive] pain.”

The government also cited four 2014 reports to the Hennepin County Sheriff’s Office of letters sent by Ivers to multiple judges that included remarks such as “I hope your family dies.”

Ivers has been described through recent court filings as unemployed, without his own home and a “self-described loner.” Prosecutors successfully used his past statements to convince an Iowa federal judge overseeing the case to keep Ivers detained before trial.

Because the alleged threat was made against a Minnesota federal judge, the chief judge disqualified the rest of the district’s bench from presiding over the case, and the Eighth U.S. Circuit Court of Appeals appointed Judge Robert Pratt to oversee the case.

Pratt also has refused to throw out Ivers’ statements to his former attorneys. Ivers’ defense team, which does not include the same lawyers who reported the threats, had argued that the statements used to charge Ivers should be protected by attorney-client privilege. Brett Kelley, an attorney for Ivers, has said that Ivers “was simply venting about an adverse court ruling” when he made the statements to the other attorneys.

Against the wishes of his legal team, Ivers testified earlier this year during an evidentiary hearing in the case, characterizing his past remarks as “arguments in the natural course of life” and referring to his “right to fight” when wronged by another person. Before being charged, Ivers prompted heightened security at hearings in his civil case, and the U.S. Marshals Service confronted him four times last year over concerning statements, including describing himself as a “walking bomb” to a court clerk.

Prosecutors now say Ivers also sent Wright a series of concerning notes throughout his litigation, including telling the judge that he was in “dire [expletive] straights!”

“I am becoming a very dangerous person!!!” he added.