Updated at 1:13 p.m. ET Wednesday

In an extraordinary move, the Trump administration has added a third deputy director to the U.S. Census Bureau amid mounting concerns of political interference with the 2020 census, the bureau announced Monday.

As the new deputy director for data, Benjamin Overholt will "support the Census Bureau in ensuring the 2020 Census data products are of the highest quality," the bureau said in a statement posted on its website.

Neither the Census Bureau nor the Commerce Department, which oversees the bureau, have responded to NPR's questions about who created the top-level position and why. It is also unclear what Overholt's exact responsibilities are.

While Census Bureau directors are politically appointed, the day-to-day operations of the federal government's largest statistical agency have been traditionally overseen by a single deputy director who is a career civil servant. Deputy Director Ron Jarmin, an economist who is also the bureau's chief operating officer, has spent more than a quarter of a century at the agency.

Overholt, a statistician who previously served with the U.S. Equal Employment Opportunity Commission and the Department of Justice, is the third political appointee to join the bureau in less than two months. At the Justice Department, Overholt worked in the voting section of the department's Civil Rights Division. Overholt also served with the U.S. Army for about 14 years, according to the bureau and a LinkedIn profile.

Overholt's name surfaced during discussions in 2017 within President Trump's now-defunct voter fraud commission, which was chaired by Vice President Mike Pence, as reported by The Guardian.

Kris Kobach — the commission's vice chair and former Kansas secretary of state who urged officials on Trump's 2016 campaign and later in the administration to add a citizenship question to the 2020 census — praised Overholt's "strong statistical abilities" and noted that Overholt conducted analysis about Kansas after seeing Kobach interviewed on TV, according to an August 2017 email released as part of a lawsuit against the commission.

"I really would like to get him on board," Kobach wrote to Mark Paoletta, Pence's top lawyer at the time, adding that if there was resistance from the Justice Department, where Overholt was working at the time, he "would like to personally elevate the request" to the office of then-Attorney General Jeff Sessions.

In an undated letter the commission also released as part of the lawsuit, Overholt appears to address Kobach as "Mr. Secretary" while expressing his "heart-felt concerns about voter fraud."

"This commission needs experienced and politically honest scientists, of which I am one," Overholt wrote, later highlighting his experience in the military and working with census and election data.

"Together this all shows that I am able to analyze all election related data, and find answers to complex questions, all while not discussing the details of my work with anyone," Overholt added.

Kobach connected with Overholt through Christy McCormick, a member of the U.S. Election Assistance Commission who previously served as an attorney with the Justice Department's voting section and recommended Overholt to Paoletta.

Using an email address under his wife Julie's name, Overholt wrote to McCormick in August 2017 asking for advice on how to get a job with the Presidential Advisory Commission on Election Integrity and confirming that he was "very interested in working in redistricting."

"When I was at DOJ, we had numerous discussions that make me pretty confident that he is conservative (and Christian, too)," McCormick wrote to Paoletta in a June 2017 email.

Overholt — who serves on the weekends as a deacon in the Seventh-day Adventist Church, according to the Census Bureau's statement — has not responded to NPR's request for comment.

In late June, the Trump administration announced a surprise addition of a second deputy director at the Census Bureau to focus on policy — Nathaniel Cogley, a political science professor who has specialized in African politics. Cogley has been joined by a senior adviser, Adam Korzeniewski, a U.S. Marine Corps veteran who was a paid political consultant to a YouTube personality known for racist pranks.

Those two appointments sparked an inquiry from the Commerce Department's Office of Inspector General, the bureau's internal watchdog group, which has asked for their resumes and documents detailing how they were put into the positions.

Professional associations of statisticians, economists and demographers have also been questioning Cogley's and Korzeniewski's qualifications for taking on newly created, top-level roles in the final months of the 2020 census.

Rep. Carolyn Maloney of New York, who chairs the House Oversight and Reform Committee, is among the Democratic lawmakers who have been calling for Cogley and Korzeniewski to be removed from their roles. Last week, the Census Bureau's director, Steven Dillingham, called the committee's request to conduct transcribed interviews with the two appointees, as well as career officials at the bureau, "overly burdensome" because it would "present substantial disruptions to the essential operations of the census" in the middle of the coronavirus pandemic.

In a statement released Monday, Maloney called the administration's announcement of Overholt's appointment "counterproductive."

"The White House should be heeding the concerns of experienced career officials at the Census Bureau, not scheming about how to rig the process for political gain," Maloney said.

The White House press office did not respond on the record to NPR's request for comment.

"It's a little late in the game to be installing senior-level officials," says Arnold Jackson, who was the chief operating officer for the 2010 census and led operations for the 1990 census. "The systems are in place. The hiring is underway. I mean, what things are you going to do?"

The administration's three recent political appointments have also stirred up confusion and anger among many of the bureau's current career staffers.

The administration has placed these additional appointees at the bureau in the wake of the failed effort to add the now-blocked citizenship question to the 2020 census that many saw as an attempt to discourage noncitizens from participating in the constitutionally mandated count of every person living in the U.S.

Less than a month after Cogley and Korzeniewski's appointments were announced, Trump issued a memo calling for the production of data that would help the president attempt to exclude unauthorized immigrants from the apportionment count, despite the 14th Amendment's requirement to include in that count the "whole number of persons in each state."

Some bureau employees are worried the new appointees will further tarnish the agency's reputation as a nonpartisan statistical institution the country relies on for essential data.

"If you read between the lines, it's pretty obvious they want to make sure the set of statistics they want released, get released, which is not a set a statistics that anyone on the career staff is comfortable producing," says a staff researcher at the bureau who agreed to speak to NPR on the condition of anonymity out of fear of retaliation in the workplace for speaking out.

With about four months until the bureau says it's planning to deliver the apportionment count to the president as part of the process for the redistribution of congressional seats among the states, the staff researcher says many bureau employees are suspicious about the timing of the latest appointee's arrival.

"We don't need another guy to come, and if we were to have another guy come, it wouldn't be someone who has never worked for a statistical agency and who is manifestly unqualified for the second- or third-highest position," the staff researcher says. "It just seems weird."

NPR researchers Nicolette Khan and Will Chase contributed to this report.

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