The FBI is investigating the security of Hillary Clinton's private e-mail server. Here's what we know about the server, who kept it secure and how that's changed. (Gillian Brockell/The Washington Post)

Hillary Rodham Clinton and her family personally paid a State Department staffer to maintain the private e-mail server she used while heading the agency, according to an official from Clinton’s presidential campaign.

The unusual arrangement helped Clinton retain personal control over the system that she used for her public and private duties and that has emerged as an issue for her campaign. But, according to the campaign official, it also ensured that taxpayer dollars were not spent on a private server that was shared by Clinton, her husband and their daughter as well as aides to the former president.

That State Department staffer, Bryan Pagliano, told a congressional committee this week that he would invoke his Fifth Amendment rights against self-incrimination instead of testifying about the setup.

The private employment of Pagliano provides a new example of the ways that Clinton — who occupied a unique role as a Cabinet secretary who was also a former and potentially future presidential candidate — hired staff to work simultaneously for her in public and private capacities.

Catch up on the controversy and read the emails

Cheryl Mills, Clinton’s chief of staff, and Huma Abedin, a close confidant who served as deputy chief of staff, both spent time working for the State Department, the Clinton Foundation or the Clintons personally.

Pagliano’s employment by the Clintons was confirmed by a campaign official in response to questions from The Washington Post. The official spoke on the condition of anonymity because of the sensitivity of the matter. A campaign spokesman declined to provide a statement.

Pagliano had served as the IT director of Clinton’s 2008 presidential campaign and then worked for her political action committee.

The Clintons paid Pagliano $5,000 for “computer services” prior to his joining the State Department, according to a financial disclosure form he filed in April 2009.

But even after arriving at State in May 2009, Pagliano continued to be paid by the Clintons to maintain the server, which was in their Chappaqua, N.Y., home, according to the campaign official and another person familiar with the arrangement. That person spoke on the condition of anonymity because the matter is under investigation.

The private pay arrangement has not previously been reported. The State Department has declined to answer questions about whether the private system was widely known within the agency or officially approved.

Asked in early August about whether Pagliano had been paid privately to maintain the server, a State Department official said that the agency had “found no evidence that he ever informed the department that he had outside income.”

This week, a different State Department official said he could not clarify Pagliano’s pay situation, citing “ongoing reviews and investigations” of Clinton’s e-mail setup.

Pagliano did not list the outside income in the required personal financial disclosures he filed each year. The State Department has said Pagliano concluded his full-time service in February 2013, which coincides with Clinton’s departure as secretary. He remains a State Department contractor doing work on “mobile and remote computing functions,” according to a State Department spokesman.

Pagliano’s attorney, Mark MacDougall, declined to comment.

MacDougall sent a letter Monday to the House Select Committee on Benghazi, which had subpoenaed Pagliano, informing the panel that his client would invoke his constitutional rights not to answer questions.

There are multiple congressional inquiries into Clinton’s e-mail use, and the FBI is looking into the security of the setup.

A spokeswoman for the Senate Judiciary Committee, which was inquiring about Pagliano’s outside employment, said that Pagliano’s lawyer informed the committee that his client would invoke his Fifth Amendment rights.

Lawmakers interested in hearing Pagliano’s account of the server’s setup and security protocols are considering whether to offer him immunity in exchange for his testimony. If they take the step, Pagliano would be compelled to appear.

State Department officials have declined to explain which agency officials knew about Clinton’s server and whether any had raised questions or concerns about how it was being handled.

“My unsatisfactory but necessary answer to that is, again, that’s not our role in this process to really answer that question publicly; that there are reviews and investigations underway that will look at possibly some of these issues is for other entities to speak to,” State Department spokesman Mark Toner told reporters this week.

Asked by NBC’s Andrea Mitchell on Friday whether anyone in her inner circle ever expressed concern about the setup, Clinton responded, “I was not thinking a lot when I got in.”

“There was so much work to be done,” Clinton continued. “We had so many problems around the world. I didn’t really stop and think — what — what kind of e-mail system will there be?”

E-mails released this week show that members of the State Department IT department’s help desk were unaware of the setup and sought information about why a correspondent was getting a “fatal error” when sending messages to Clinton’s address. The tech support team “didn’t know it was you,” an aide e-mailed Clinton.

Federal regulations allow employees at Pagliano’s level to have outside employment but require that the extra income not exceed 15 percent of their government salary. Employees must also ensure that their outside work not create a conflict of interest with their government job.

By early 2013, as Clinton was preparing to conclude her time as secretary of state, she was looking to upgrade the system’s security and durability, people briefed on the server have said. The system had crashed for days during Hurricane Sandy in October 2012, disrupting her e-mail abilities.

To find a company to take over for Pagliano, the Clintons turned to Tania Neild, a technology broker whose company, InfoGrate, is in Bronxville, N.Y., about 20 miles from their home.

In January 2013, weeks before Clinton’s departure from Foggy Bottom, Neild alerted a small Denver-based technology firm, Platte River Networks, to a possible contract, according to Andy Boian, a spokesman for the tech firm.

Boian said Neild’s notice included no reference to the Clintons and the company submitted a proposal for the work without knowing the identity of the famous potential client.

Boian said the company learned that it might be working for the former president and former secretary of state in mid-
February of 2013, when executives were told that they were finalists for the work. The Clintons hired Platte River that June. The company has said it moved the Clintons’ server at that time from the couple’s home to a data storage facility in New Jersey, where it sat until it was turned over to the FBI last month.

Neild said in an interview with The Post that she could not confirm that she worked for the Clintons because all of her clients have nondisclosure agreements about their work.

But she said her business is helping wealthy families manage private servers and e-mail systems, and she confirmed that she works regularly with Platte River Networks.

“They are a company with the utmost integrity,” Neild said.

This story has been updated.

Tom Hamburger, Karen Tumulty and Alice Crites contributed to this report.