Hillary Clinton’s already bad week just got worse. On Tuesday, former State Department employee Bryan Pagliano skipped a congressional hearing about the e-mail server he set up in Clinton’s upstate New York residence, defying a subpoena ordering him to appear. Two other I.T. specialists, who worked for an outside firm that managed the server, appeared before the House Oversight Committee, but invoked the Fifth Amendment in response to every question.

A furious Representative Jason Chaffetz, the Republican chairman of the committee, told observers during the hearing that he had sent Pagliano a subpoena to appear at the hearing, and that he would look into legal recourse. “He should be here,” he said, according to The Hill. “When you are served a subpoena by the United States Congress, that is not optional.”

Pagliano, for his part, hadn’t planned on showing up. In a statement delivered the day before the hearing, Pagliano’s lawyers notified the committee that he would not testify, arguing that their client had already testified before another Republican-led committee, and calling the hearing “a transparent effort to publicly harass and humiliate our client for unvarnished political purposes.”

Pagliano has already spent years in the public spotlight. According to the Daily Beast, Pagliano had initially worked for Clinton when she was secretary of state, pulling in an unusually high salary for “what appeared to be an ordinary tech support job.” Unbeknownst to the most people at the State Department, however, Pagliano had a secret job on the side maintaining Clinton’s “homebrew” e-mail server, which was kept in the basement of her Chappaqua home, allowing her to send e-mails that were not captured by State Department servers. (Clinton has given various explanations for the server’s existence, ranging from her desire to have one device, to her following advice from Colin Powell.)

Ever since, Pagliano has become a target for Republicans hoping to land charges on Clinton, and has been called into questioning for numerous hearings and depositions; sometimes about Clinton’s actions during the 2012 Benghazi raid, sometimes about the potentially classified information that had passed through the server itself. Throughout this ordeal, he has repeatedly invoked his Fifth Amendment right against self-incrimination. (Once, when he was being deposed by the conservative watchdog group Judicial Watch, he invoked his Fifth Amendment right more than 125 times.)

But never before had he simply refused to testify, a point that the Republicans on the committee emphasized as they argued that Pagliano had flouted the law, while Democrats contended that the hearing could have led to self-incrimination and breached the limits of his reported immunity deal with the F.B.I. “It puts him in jeopardy coming before this committee while that criminal referral is in existence,” said Democratic congressman Stephen Lynch, according to The Hill. “He’s an American citizen; I know the Constitution gets in the way of this committee sometimes.”

By attempting to save his own skin, however, Pagliano may have created more problems for Clinton’s presidential campaign. Over the past few days, more questions have arisen over the candidate’s penchant for secrecy, which blew up most recently when the campaign failed to disclose that the Democratic nominee had been diagnosed with pneumonia. Though the campaign had feared that Clinton’s Republican foes would use her illness to question her presidential stamina, as Donald Trump and his surrogates have done in the past, she received more backlash from fellow Democrats, who were exasperated that her paranoia had turned an otherwise mundane illness into a metaphor for her personal flaws. With the man at the center of Clinton’s e-mail scandal skipping a hearing instead of enduring Representative Trey Gowdy’s questioning, Republicans now have yet another reason to criticize her.