Gina Haspel, the veteran CIA undercover officer President Donald Trump has picked to head the agency, is supported by many in the US intelligence community but has faced criticism for overseeing a secret CIA prison in Thailand where detainees were tortured.
Intelligence officers who served with her and congressional officials said that in 2002, during Republican President George W Bush's administration, she was responsible for the secret prison codenamed "Cat's Eye". Two suspected members of the al-Qaeda militant group were subjected to waterboarding and other harsh interrogation techniques at the facility.
Three years later, still during Bush's presidency, she carried out an order to destroy videotapes of the waterboarding, which simulates drowning and is considered a form of torture, according to those people.
Haspel is generally held in high regard at the CIA, working as deputy director under Mike Pompeo, who Trump picked to be the next secretary of state on Tuesday after firing Rex Tillerson from the post.
If confirmed by the Senate, Haspel would become the first woman to lead the Central Intelligence Agency. But she could face close scrutiny in her confirmation hearings over her involvement in "black site" facilities, so called because their existence is unacknowledged by the US government.
Her nomination faces an uncertain future in the Senate, which Trump's fellow Republicans control 51-49. She could be opposed by all the Democrats. Republicans also have lost the vote of Senator Thad Cochran, who said he will resign on April 1, and other Republicans may oppose her.
"The torture of detainees in US custody during the last decade was one of the darkest chapters in American history," said Republican Senator John McCain, who was himself tortured as a prisoner of war in Vietnam.
"Ms Haspel needs to explain the nature and extent of her involvement in the CIA's interrogation program during the confirmation process."