A powerful congressional committee voted today to hold Hillary Clinton’s former technology director in contempt of Congress for refusing to testify about her private email server and his role in maintaining it while he worked for her at the State Department.

The House Oversight and Government Reform Committee had been trying unsuccessfully to obtain testimony from Bryan Pagliano, who has been one of the key figures in the email controversy that continues to dog Clinton in the home stretch of the presidential election.

Pagliano is believed to know better than most how the server was set up and maintained and what may have happened to emails that were deleted from the system, including after it was publicly revealed that Clinton was using a private server.

Pagliano had struck an immunity deal with the Department of Justice that allowed him to talk to FBI agents about the email server without fear of being prosecuted for any crimes. Government lawyers showed members of the committee a copy of that agreement, which had been placed under seal by a federal judge, on Thursday morning.

Committee Republicans have long maintained that Pagliano’s immunity deal means he has no reason to fear giving testimony to Congress, and nothing in the terms of the deal appears to have persuaded them otherwise. The committee had used U.S. Marshals to serve a subpoena at Pagliano’s office demanding that he appear Thursday morning. Unsurprisingly, he did not, having already accused the committee chairman through his lawyers of using Pagliano’s testimony as a spectacle to embarrass Clinton just six weeks before the presidential election.

The subpoena “betrays a naked political agenda and furthers no valid legislative aid,” Pagliano’s lawyers wrote in a letter to the committee. The FBI has already decided not to prosecute Clinton or her aides over the email server.

Pagliano has long been a person of interest to the committee’s investigation, which has also sought to determine whether Clinton perjured herself when she testified under oath about her email server before the House panel investigating the terrorist attacks in Benghazi, Libya, which occurred on her watch.

In blasting Pagliano for his decision not to comply with the committee’s subpoena, Chaffetz suggested that Pagliano may have deliberately tried to hide his own emails from his time working for Clinton at the State Department. Among the questions Pagliano could answer is “how he was able to prevent the State Department from discovering most of his emails,” Chaffetz said.

Chaffetz was referring to the fact that the State Department was unable to find copies of Pagliano’s emails in a backup file, or archive, known as a .pst file, for the entire time Clinton was Secretary of State and Pagliano was working for her maintaining the private server.

Curiously, State officials did find such an archive for the period after Clinton had left the department, when Pagliano was still working for the department as a contractor. And State was also able to find the archived emails of other top Clinton aides, which have been turned over as part of Freedom of Information Act lawsuits brought by watchdog groups and news organizations, including The Daily Beast.

Once it was clear Pagliano would not be testifying, Republican and Democratic lawmakers spent their time hurling accusations at each other and turning the hearing into an opportunity to bash each party’s nominee for president.

Rep. Elijah Cummings, the committee’s top Democrat, accused Chaffetz of “an abuse of authority,” noting that Pagliano’s testimony was unlikely to shed any new light on Clinton’s email practices.

If the committee really intends to discover whether officials or candidates for office have broken any laws, Cummings asked, “Then where is our investigation of Donald Trump, his potentially fraudulent business practices, his campaign's potential connections to Russian hackers?” The committee has held no hearings on those subjects or Trump’s “charitable foundation’s illegal campaign donations,” Cummings said.

The committee was focused “exclusively and obsessively with Secretary Clinton, and that is for political reasons,” Cummings continued.

Republicans, however, defended their decision to subpoena Pagliano and hold him in contempt as vital to preserving the system of checks and balances and their legal oversight role.

“Subpoenas are not optional,” Chaffetz said. Recognizing that a contempt finding was an extraordinary measure, Chaffetz insisted that “this committee cannot operate...if subpoenas are ignored.”

The contempt finding now faces a vote before the full House, and it would then be passed onto the U.S. attorney for the District of Columbia, Channing D. Phillips, who would decide whether to prosecute Pagliano. Phillips was appointed by President Obama in 2015.

The House committee has been digging into the role of other Clinton technology staff. This week, Chaffetz demanded that Reddit preserve deleted posts that may have been written by an employee of Platte River Networks, the company that Clinton later hired to maintain the server. The employee, who is believed to be an engineer named Paul Combetta, sought the advice of Reddit users on how to strip out the email address of someone he described as a “VIP” before a set of emails were turned over. He appears to be referencing work to collect Clinton’s emails and then turn them over to the State Department after she left office.

Combetta, along with two others who had worked on the Clinton server, also refused to testify last week before Chaffetz’ committee, but they did show up for a hearing. Combetta is also believed to be the unnamed employee in the FBI’s report on the Clinton email investigation who is said to have wiped emails off of her server even after lawmakers had asked her lawyers to produce all copies of her emails.

The FBI appears to have investigated the question of whether Combetta was directed to delete emails after the committee asked for them. Investigators discovered a “work ticket, which referenced a conference call on March 31, 2015, with Platte River, Clinton aide Cheryl Mills, and David Kendall, Clinton’s longtime attorney who oversaw the process of separating her work emails from personal messages.

Platte River’s attorney advised the employee “not to comment on the conversation with Kendal based upon the assertion of the attorney-client privilege,” the FBI found.

Mills told the FBI “she was unaware that [the employee] had conducted these deletions and modifications in March 2015.” Clinton stated “she was also unaware” of the deletions.

But what exactly was discussed in that conference call, the FBI never found out.