The parents of two Americans killed in a 2012 attack in Benghazi in Libya are suing Hillary Clinton.
Patricia Smith and Charles Woods, parents of Sean Smith and Tyrone Woods, filed a lawsuit against the Democratic presidential nominee for wrongful death and defamation.
The suit, which was filed on behalf of the parents by the conservative group Freedom Watch, claims the former Secretary of State's use of a private email server contributed to their sons' death.
The parents also accuse Mrs Clinton of defaming them in statements to the media.
Islamic militants attacked a US diplomatic compound in Benghazi in 2012 and killed four Americans, including ambassador Chris Stevens, while Mrs Clinton was Secretary of State.
A House Republicans committee cleared Mrs Clinton of any wrongdoing earlier this year but the issue has dogged her presidential campaign.
The parents, who have both spoken out against Mrs Clinton, said her "'extreme carelessness' in handling confidential and classified information on her private server may have revealed the location of State Department employees in Libya.
Those details could have been obtained by "hostile adversaries" who may have hacked her server and ultimately led to their sons' deaths, the parents said.
FBI director James Comey announced last month that it was "possible that hostile actors gained access" to Mrs Clinton's email server, but added the agency did not find conclusive evidence that it was hacked.
Chris Stevens's sister Anne Stevens told The New Yorker earlier this year she did not blame Mrs Clinton, saying it was "inappropriate" to make the Benghazi attacks a political issue.
"The Benghazi mission was understaffed. We know that now. But, again, Chris knew that," she said.
"It is not something they did to him. It is something he took on himself."
The suit also claims Mrs Clinton made "false and defamatory statements negligently, recklessly and purposefully and/or intentionally with malice" in public statements.
Mrs Clinton blamed the attack on a controversial YouTube video mocking the Islamic prophet Muhammad, but later denied making those statements, the parents said.
Clinton campaign spokesman Nick Merrill said in response to the suit: "While no one can imagine the pain of the families of the brave Americans we lost at Benghazi, there have been nine different investigations into this attack and none found any evidence whatsoever of any wrongdoing on the part of Hillary Clinton."
-BBC