Rep. Trey Gowdy, the Republican point man in the House investigation of Hillary Clinton's email accounts, announced Wednesday he will not seek re-election in 2018.

Gowdy, a former federal prosecutor, is chairman of the House Oversight Committee and a member of the House Intelligence Committee, which is investigating alleged Russian meddling in the 2016 election.

"There is a time to come and a time to go. This is the right time, for me, to leave politics and return to the justice system," the 53-year-old South Carolina Republican tweeted.

Rep. Trey Gowdy tweet

Gowdy was elected in the 2010 tea party wave that returned control of the House to Republicans.

He headed a partisan panel that investigated the deadly Sept. 11, 2012, attack on American diplomats in Benghazi, Libya. The panel revealed the existence of former Secretary of State Clinton's private email server. Controversies involving her use of email damaged her failed 2016 presidential campaign.

Gowdy's announcement came two days after Republican Rep. Rodney Frelinghuysen of New Jersey, the powerful chairman of the House Appropriations Committee, announced that he will not seek re-election. Foreign Affairs Chairman Ed Royce and Oversight Chairman Darrell Issa, both California Republicans, also have recently opted against difficult re-election bids.

Republicans hold a 238 to 193 seat majority in the House, with four current vacancies. That means Democrats need to pick up 25 GOP seats to take over the House. According to NBC News' count, at least 20 Republican incumbents have said they will retire this year.

Gowdy's district voted for then-candidate Donald Trump over Clinton by 60 percent to 34 percent in 2016. In that election, he won by a 36-point margin, NBC said.

—The Associated Press and NBC News contributed to this report.