A former CIA officer and diplomat who has repeatedly denied playing a role in one of the most notorious U.S. counterterrorism programs is set to become the only American held accountable for it -- and claims the Obama administration has abandoned her.

Sabrina De Sousa, who is stuck in Portugal and awaiting extradition to Italy over her alleged role in the rendition of a terror suspect years ago, claims the State Department has ignored repeated requests to intervene on her behalf. She and her lawyers are particularly critical of Hillary Clinton, who still has not commented on the case.

Mark S. Zaid, an attorney who previously worked with De Sousa, told FoxNews.com his firm made “multiple efforts” to reach out to the State Department -- specifically then-Secretary of State Clinton -- and that “every time we were completely rebuffed with silence.”

He said one of his letters was even "deceptively" classified “to limit my ability to create a public furor over how Sabrina had been and continues to be mistreated.”

De Sousa, a naturalized American from India, was arrested in Portugal last October and earlier this month lost her latest court bid to halt her extradition to Italy. She faces four years in prison there over her alleged role in the rendition of a suspected terrorist 13 years ago.

De Sousa has launched numerous unsuccessful bids over the years to clear her name, but has received little known help from the government she served for more than a decade.

If she’s sent to prison, she would become the first CIA officer and U.S. diplomat imprisoned over the controversial rendition program.

Implemented under President George W. Bush, the program transferred terror suspects to other countries for detention and interrogation. De Sousa, along with about two dozen other CIA agents and an Air Force official, were convicted in absentia in Italy in 2009 on kidnapping and other charges related to the abduction of Osama Mustapha Hassan Nasr, known also as Abu Omar, under the rendition program.

Omar, a radical cleric, was taken while walking down a street in Milan and flown to Egypt where he was held prisoner for four years without a trial before eventually being released. Omar claims during that time he was tortured.

Omar also was convicted in absentia in Italy of “criminal association for the purposes of international terrorism” and sentenced to six years in prison. Prosecutors claim he collaborated with 13 other suspected terrorists between 2000 and 2003 with the intent of carrying out terrorist attacks around the world.

Around the time of the rendition, De Sousa, 60, worked under diplomatic cover and was stationed in Milan.

On the specific day in question, though, De Sousa claims she was chaperoning her son’s school ski trip in northern Italy – about 200 miles from Milan.

De Sousa recently detailed her frustration over the situation to VICE. During the in-depth interview, she didn’t pull punches at who she thinks is hurting her shot at freedom.

“There needs to be an explanation instead of a no comment,” De Sousa said about Clinton’s careful avoidance of the issue. “She already has the issue of Benghazi, which was diplomatic. And now we have a U.S. diplomat going to prison, that’s two things.”

De Sousa believes Clinton could still do the right thing.

“I think the most important thing Secretary Clinton can do now is comment,” De Sousa told VICE. “So going in, if she becomes president, then at least everyone knows her position on it.”

A State Department official told FoxNews.com that they are aware of the De Sousa situation:

“We have seen reports that a Portuguese Court has acceded to the Italian government’s request for the extradition of Sabrina de Sousa. We refer you to the Italian and Portuguese governments for further information.”

De Sousa’s extradition was recently raised during a European Parliament hearing where a resolution was passed calling upon member states to formally investigate Europe’s role in U.S. renditions.

Ana Gomes, a member of the European Parliament, called De Sousa a “scapegoat” and said those truly responsible for renditions were being protected.

VICE also spoke with Abu Omar, who said he supports a pardon or immunity for De Sousa.

The irony isn’t lost on De Sousa.

“A former agency employee said to me – ‘How embarrassing is it going to be for the CIA when the terrorist starts to support you in this whole story?’” she reportedly said.

Glen Caplin, a spokesman for Clinton's campaign, told FoxNews.com that they "can not comment on the specifics of a case that is working its way through the legal systems of two other countries" and deferred "any questions to the U.S. government agencies."