WASHINGTON — House Democrats will participate in the special Republican-led select committee investigating the deadly 2012 attack in Benghazi, Libya, despite serious concerns within the party that the inquiry is an election-year ploy to energize core GOP voters.

Minority Leader Nancy Pelosi announced on Wednesday that she will appoint the full complement of five Democrats on the 12-member panel, tapping lawmakers who have been involved in previous congressional probes of the Sept. 11, 2012, assault on the U.S. diplomatic outpost.

Four Americans, including U.S. Ambassador Chris Stevens, died in the attack when militants stormed the mission. Republicans have accused the Obama administration of misleading Americans about a terror attack weeks before the election.

“I believe we need someone in that room to simply defend the truth,” said Rep. Elijah Cummings of Maryland, the top Democrat on the Oversight panel.

Speaker John Boehner, R-Ohio, had selected Rep. Trey Gowdy, R-S.C., a prosecutor, to be the panel’s chairman along with six other Republicans.

Democrats who also will participate are Adam Smith of Washington state, the top Democrat on the Armed Services panel; Adam Schiff of California, a member of the Intelligence Committee; Linda Sanchez, also of California, who is on Ways and Means’ oversight subcommittee; and Tammy Duckworth of Illinois, who serves on Armed Services.

Democrats have been divided over whether to boycott the investigation, the eighth probe. Some Democrats have called the new inquiry a political sham designed to embarrass the White House and rough up former Secretary of State Hillary Rodham Clinton, a potential 2016 presidential candidate.

Among Democratic leaders, Rep. Jim Clyburn of South Carolina reiterated his reservations on Tuesday. Clyburn had said, “If you’re going to have a hanging, don’t ask me to bring the noose.”

Pelosi said she “could have argued this either way. Why give any validity to this effort?”

Other Democrats say they must participate in the select committee to ensure they have a role in questioning witnesses.

“We can’t simply let the Republicans run the show,” Smith said.

The special investigation means high-profile hearings in the months leading up to the elections, with Republicans likely to target current and former administration officials. Almost certain to be called to testify is Clinton.

The panel is authorized to work past November’s midterm elections, when the GOP hopes to win control of the Senate and tighten its hold on the House.

Multiple probes have faulted the State Department for inadequate security in Benghazi, leading to four demotions. No attacker has been arrested.