Senator Dianne Feinstein (D-Calif.) questions witnesses before the Senate Judiciary Committee during a hearing about legislative proposals to improve school safety in the wake of the mass shooting at the high school in Parkland, Fla., on Capitol Hill on Wednesday. (Joshua Roberts/Reuters)

The Democrat who wrote the Senate’s seminal report on the CIA’s use of enhanced interrogation techniques criticized as torture wants the agency to declassify documents detailing the role Gina Haspel, President Trump’s nominee to take over as director, played in overseeing the practice and attempts to destroy evidence of it.

Sen. Dianne Feinstein ­(D-Calif.), a senior member of the Intelligence Committee, wrote in a letter Thursday that senators need “the complete picture” of Haspel’s involvement to “fully and fairly” review her fitness for the job. The letter was sent to current CIA director Mike Pompeo, who has been nominated to become Trump’s secretary of state, and Haspel, who serves as the agency’s deputy director.

“The American people deserve to know the actual role the person nominated to the director of the CIA played in what I consider to be one of the darkest chapters in American history,” Feinstein wrote.

Haspel, who if confirmed would be the first woman to lead the agency, is a longtime CIA employee. During her tenure, she was in charge of a “black site” prison — a facility where detainees were interrogated using methods such as waterboarding. She also was among those officials involved in the decision to destroy video of interrogation sessions.

As a candidate, Trump suggested the United States reinstate waterboarding and other enhanced interrogation techniques, a proposal he has not followed through on as president. But several senators pointed to Haspel’s history as a reason to be concerned about her nomination, including Sen. John McCain (R-Ariz.), himself a victim of torture during the Vietnam War.

“Ms. Haspel needs to explain the nature and extent of her involvement in the CIA’s interrogation program,” McCain said in a statement this week, noting that her career dovetailed with the harsh interrogation program “on a number of occasions.”

Feinstein, however, was noticeably reserved when the announcement was made, nodding to her past concerns with Haspel’s record but telling reporters that she has been “a good deputy director.”

Feinstein is credited with shining a light on the interrogation techniques used after the 9/11 attacks. The 6,000-page report was the product of a five-year investigation, a summary of which was publicly released in 2014.

But on Tuesday, Feinstein appeared to stress that when Haspel was implicated in such practices, the laws against them were not as clear.

“The difficult problem is intelligence agencies work aside from the law. So our job doing oversight is really to do our level best to keep them within the law,” Feinstein said on Tuesday. “And fortunately the law, thanks to Senator McCain, has been changed. And torture is now illegal in the United States. That’s with specificity. And I think that’s important. So it’s a different day.”

On Wednesday, Senate candidate Kevin de Leon, a Democrat who is vying for Feinstein’s seat questioned why the senator did not more strongly condemn Haspel. The Senate, he wrote in a tweet, “should not equivocate on rejecting Trump’s pro-torture CIA nominee. John McCain understands that. Why doesn’t Dianne Feinstein?”

The Intelligence Committee is scheduled to begin considering Haspel’s nomination in April.