Rep. Elizabeth Esty, D-Conn., announced Monday that she would not seek re-election this November amid accusations that she failed to protect her female staffers from a former chief of staff accused of harassment and abuse.
In statement posted on Facebook, Esty said: "I have determined that it is in the best interest of my constituents and my family to end my time in Congress at the end of this year and not seek re-election."
Esty had come under pressure to resign after reports by the Connecticut Post and The Washington Post revealed that Esty allowed her then-chief of staff, Tony Baker, to remain on the job in May 2016 despite knowledge of allegations that he physically harmed and threatened to "kill" another staffer.
"Too many women have been harmed by harassment in the workplace," Esty wrote. "In the terrible situation in my office, I could have and should have done better. To the survivor, I want to express my strongest apology for letting you down."
National Republican Congressional Committee spokesman Matt Gorman said Esty's announcement marked "a sad day for Connecticut's 5th district.
"Elizabeth Esty's coverup over her staffer's domestic violence scandal was as reprehensible as it was morally bankrupt," Gorman said. "The NRCC is ready to win this competitive seat this fall. Democrats won't be able to distance themselves from the stain Esty left on their brand."
Esty has represented the district since 2013. A Republican was last elected to the seat in 2004. The district includes Newtown, where the Sandy Hook Elementary School shooting massacre occurred. Esty has been a vocal advocate for stronger gun laws but has been mostly unable to pass any new federal legislation since the December 2012 shooting. She recently attended President Donald Trump's White House meeting on guns and other issues following the Parkland, Fla., school shooting.
Connecticut Democrats praised Esty's decision not to seek re-election.
"The truth is, too many facts about how this incident was handled fall short of appropriate standards for responsible and responsive leadership," said Gov. Dannel P. Malloy, who had not publicly called for Esty to resign.
"Congresswoman Esty made a difficult decision, but the right one for her and the constituents of her District," Rep. Rosa DeLauro said in a statement.
Earlier Monday, Esty asked the House Ethics Committee to determine whether she did anything wrong in handling Baker's firing.
In her letter to committee members, Esty said she learned through a third party in 2016 about possible misconduct by Baker involving a former staffer, who worked in her office from January 2013 to March 2015. Esty has said she fired Baker three months later after receiving an internal investigation report that revealed improper behavior by Baker that affected multiple female staffers.
However, news reports last week revealed that Baker received a $5,000 taxpayer-funded severance payment from Esty, as well as a recommendation that landed him a job at the pro-gun control group Sandy Hook Promise. Staffers said Esty repaid the federal government last week with her personal funds.
Before news of the controversy broke, Esty had issued press releases calling for tougher harassment protections for congressional staffers and was among those demanding that then-U.S. Rep. John Conyers, D-Mich., resign amid allegations of misconduct.
A spokesman for Baker, the former chief of staff, told the Connecticut Post and The Washington Post that he denies some of the allegations. A phone number listed for a Tony Baker in Columbus, Ohio, where the spokesman said the former chief of staff was living, was disconnected.
An aide to House Minority Leader Nancy Pelosi, D-Calif., told Fox News that Esty informed Pelosi of her decision to not seek re-election in a phone conversation Monday. Earlier, Pelosi commended Esty's former employee Anna Kain for coming forward and telling her story, but stopped short of calling on the congresswoman to resign.
"As Congresswoman Esty has acknowledged, her actions did not protect Ms. Kain and should have," Pelosi said in a written statement. "Congresswoman Esty has now appropriately requested an expedited review by the Ethics Committee."
Fox News' Mike Emanuel and The Associated Press contributed to this report.