The State Department staffer who helped Hillary Clinton set up her private email server was paid to do so — but separately from his government job, a campaign aide confirmed to NBC News.

A campaign official said the personal server allowed Clinton to have control over her emails as Secretary of State, and by retaining the staffer and paying him personally, it also meant taxpayer dollars wouldn’t be spent on setting it up, The Washington Post first reported Saturday.

Bryan Pagliano, the former State Department staffer who also worked for Clinton during her 2008 presidential campaign, has been identified in digital records as the person who set up her email server in 2009. He has vowed to invoke the Fifth Amendment and refuse to answer questions after a congressional committee subpoenaed him, MSNBC confirmed this week.

Related: Hillary Clinton Tells NBC News She Is ‘Sorry’ for Email Confusion

Clinton’s use of an unsecured private email server instead of an official government server has become a campaign issue as she runs for the Democratic presidential nomination. The FBI is probing whether any classified information was mishandled by her or her staff, who also had access to the server.

In an exclusive interview with NBC News/MSNBC’s Andrea Mitchell on Friday, Clinton said she was “sorry” over the controversy the email server issue has caused, but she fell short of apologizing for the decision to use it.

“At the end of the day, I am sorry that this has been confusing to people and has raised a lot of questions, but there are answers to all these questions,” Clinton said. “And I take responsibility and it wasn’t the best choice.”