A federal grand jury has indicted John Anthony Proia III, a 41-year-old from Waltham, Massachusetts, on one count of cyberstalking. The case accuses him of targeting conservative podcaster and former Trump administration official Katie Miller dozens of times with menacing phone calls and messages. He was arrested Thursday by an FBI task force.

Court papers do not name the victim, but a person familiar with the matter confirmed to The Associated Press that she is Miller, whose husband, Stephen Miller, is the White House deputy chief of staff. Prosecutors described her only as a former political adviser and prominent Republican who lives near Washington and is married to a high-level federal employee.

The U.S. attorney's office said Proia contacted her at least 40 times between Aug. 3 and Sept. 23, using calls, text messages and voicemails from a constantly shifting set of phone numbers. The numbers came from free internet calling apps that let users conceal their identity and easily generate new ones, according to the charging documents. Some calls came late at night, and prosecutors said they carried a menacing tone and were laced with expletives. Some of the voicemails and texts were about both Miller and her husband.

He is also accused of sending disturbing messages to her parents. One of them, according to prosecutors, read: "My god, how can you be proud of this filth?" A text to her father quoted in the indictment mocked her marriage to a man it called a "Jewish Nazi/white supremacist" and asked whether her parents had raised her "to be trash."

U.S. Attorney Leah Foley said the indictment alleges that Proia "repeatedly and relentlessly targeted the victim, her husband and her family with deeply disturbing communications that profoundly disrupted their lives." People who use technology to harass or intimidate should understand that attempts to stay anonymous "will not shield them from prosecution," Foley said. "We will find you, and we will hold you accountable." "Terrorizing someone isn't some sick game, it's a crime," said Ted Docks, who leads the FBI's Boston office.

An attorney listed for Proia did not immediately answer an emailed request for comment Thursday, the AP reported.

The investigation had already helped set off upheaval at the FBI's Washington field office, where the office's leader recently reassigned two top counterterrorism supervisors, partly out of dissatisfaction with how they had approached the Miller inquiry, according to people familiar with the matter. Sources that included former FBI officials told MS NOW that the two had questioned the legality and legitimacy of a request that their counterterrorism section conduct a threat assessment on the person believed to be making the calls. The FBI confirmed the demotions.

Darren Cox, the assistant director in charge of the Washington field office, said FBI Director Kash Patel did not order the moves, calling them "a personnel decision made at the Washington field office level alone based on our constant evaluation of mission needs." "Any suggestion otherwise is false," Cox said. White House spokeswoman Lauren Bis said the Millers had never interacted with or met the reassigned officials and that senior FBI leaders "determined they were stifling investigations into very serious threats."

Three days before the indictment, Bloomberg Law reported that investigators had traced the calls to a Boston-area man who had been phoning Miller. Federal prosecutors in Boston were under mounting pressure to charge him despite internal concerns about the evidence, the outlet said, and career prosecutors there shared some of the FBI's doubts about whether they could prove a crime had occurred.

Former Justice Department officials familiar with the case told Bloomberg Law that the facts did not appear to meet the standard for a federal threats case and would have been better handled by local police. At that point, the specific charge and charging method had not been firmly resolved, the report said, and a spokesperson for the U.S. attorney's office in Boston declined to comment.