WASHINGTON  — The photo that became an Internet meme — Hillary Rodham Clinton, wearing sunglasses, staring at her BlackBerry — troubles Republicans on the House committee investigating the deadly attacks in Benghazi, Libya, for what they say is an incomprehensible omission.

Chairman Trey Gowdy, R-S.C., wants to know why the panel has no emails from Oct. 18, 2011, the day the photo was taken as Clinton, then the secretary of state, was en route to Tripoli. In fact, the committee says it has no emails at all from Clinton’s trip to Libya, which occurred just days before longtime Libyan ruler Moammar Gadhafi was killed.

Eleven months later, in September 2012, terrorist attacks on the U.S. mission in Benghazi killed U.S. Ambassador Chris Stevens and three other Americans.

Gowdy said in an interview that it “strains credulity” to believe that while on a trip to Libya to discuss Libyan policy “there’s not a single document that has been turned over to Congress.”

The recent disclosure that Clinton, a likely Democratic candidate for president in 2016, relied on personal emails to conduct government business has breathed new life into the Benghazi panel’s investigation, which had threatened to stall amid accusations of partisanship on both sides.

In the past week alone, Gowdy has issued a subpoena for Clinton’s emails and called for an independent review of Clinton’s private email server. House Speaker John Boehner, meanwhile, has not ruled out a vote in the full House to force Clinton to turn over her server, setting up a high-stakes confrontation between the GOP-led Congress and Clinton, widely considered the Democratic front-runner for president.

The House Oversight and Government Reform Committee said it will send a letter Friday to the State Department and Clinton formally requesting answers to a series of questions about Clinton’s emails.

Gowdy called the Libyan trip emblematic of “huge gaps” — stretching for months — in documents turned over to the committee by the State Department. “It’s not up to Secretary Clinton to decide what is a public record and what is not,” said Gowdy, who wants Clinton to appear before his committee at least twice: once to talk about emails and a second time to offer testimony on Benghazi.

Gowdy, a former prosecutor, denied claims by some Democrats that he is looking to expand the jurisdiction of the Benghazi committee to focus on Clinton, possibly slowing or derailing her presidential bid.

“It’s only about her now because of the new revelations,” said the South Carolina Republican. “To me this is still about Benghazi.”

The committee’s turn in the spotlight comes just a few weeks after Democrats complained that the Benghazi investigation was moving at a “glacial” pace and that Gowdy was leading the panel on increasingly partisan path. In late January, Gowdy vowed to “ratchet up” an inquiry he said was being hobbled by resistance from the Obama administration.

The inquiry comes after several Republican-led House investigations debunked various conspiracy theories about the attacks. A 2014 report by the House Intelligence Committee determined there was no intelligence failure, no delay in sending a CIA rescue team, no missed opportunity for a military rescue and no evidence the CIA was covertly shipping arms from Libya to Syria.

Military officers told two other GOP-led House committees that there were no “stand-down orders,” and the committees’ investigations found that incomplete and contradictory information complicated efforts to get Americans out of Libya.