Washington (CNN) Jessikka Aro, a Finnish investigative journalist with a history of breaking stories on Russian propaganda efforts, had been slated to receive a prestigious award in Washington along with several other women selected by the State Department for their courage in the face of great risks overseas.

Suddenly and without warning, the honor to appear at the International Women of Courage awards with Secretary of State Mike Pompeo and first lady Melania Trump was rescinded -- with no explanation from the department.

After a Foreign Policy report suggested that the State Department may have retaliated against her because of her criticism of President Donald Trump on social media, State Department deputy spokesperson Robert Palladino asserted it was a miscommunication and that she had been "incorrectly notified" of her award. He called it a "regrettable error," saying Aro actually "had not" been a finalist.

But internal communications reviewed by CNN show that the State Department and US embassy officials in Finland had been in talks with Aro for several months, extensively communicating with her about the award, her travel documents, her itinerary in Washington and her bio, which had been approved by eight State Department officials.

Then, two weeks after an official asked her to provide a list of her social media accounts, the honor was abruptly rescinded and the invite to attend the event was canceled.

"That's the last step for us, then Washington will have everything they need," said a Helsinki embassy official in a February 8 email to Aro requesting "all your social media handles."

Democrats calling for an investigation

The documents were obtained by Democrats on the Senate Foreign Relations Committee, who have now written a letter to the State Department's inspector general to demand an investigation into allegations that the invite was rescinded because of Aro's criticism of Trump, calling the episode "disturbing."

"If the department rescinded the award because of statements made by a journalist, exercising her right to freedom of speech, it would mean that the Department is using political fealty to the President as an eligibility criteria for receiving a government award designed to highlight courage," said Sen. Bob Menendez, the top Democrat on the panel. "Furthermore, misleading the public and Congress about the true reasons behind its actions would harm the Department's reputation here in the United States and around the world, and undermine its credibility regarding future pronouncements from the press podium."

At a State Department briefing on March 7, the day of the awards, Palladino was asked whether Aro's criticisms of the President had cost her the honor. He said he was "not going to be able to go further into weighing the merits of who was selected, whether one person had more merit versus the other."

"But I can say we regret the error and we've got to do better in that regard," he said.

In comments to CNN Thursday, Palladino reiterated he was "not going to comment on the internal deliberations behind the selection process," but acknowledged that "multiple errors were made that led to the incorrect notification."

Palladino said he was aware that some members of the Senate Foreign Relations Committee had asked for an investigation from the State Department Office of Inspector General.

"As always, we will fully cooperate with any OIG investigation. We are already takings steps to ensure that this does not happen again and we would welcome additional recommendations from the OIG to improve our processes," Palladino said.

The State OIG did not respond to a request for comment.

Aro told CNN on Thursday that she does not accept the State Department's explanation that it was an "error."

"For me personally, it was an utterly surprising life event to watch the TV news in Finland and find the State Department spokesman spreading false statements to the international press," she said in an email.

"In addition, the 'error' explanation is demeaning towards those US diplomats, who had named and accepted me as an IWOC awardee, and who -- according to my knowledge -- didn't commit 'errors' in the process," she said.

Aro also suggested that the matter should be investigated to expose whether her tweets critiquing Trump were the reason the award was revoked.

"If some DC official used those or similar expressions of my freedom of speech as the main reason to rescind my award, that unfortunately hinders the whole idea of the International Women of Courage Award, which is to promote human rights, such as freedom of speech, and which was the basis for my nomination in the first place," she told CNN.

Communications with embassy officials in Helsinki began in October, when an employee asked if she would accept a nomination for the award. They continued in November, followed by more than a dozen correspondences in January and February.

On February 8, an embassy official requested all of her social media handles, a request which Aro complied with. A State Department spokesperson said they asked all participants for their social media handles as part of their biographies.

On Twitter, Aro has repeatedly poked fun and criticized Trump, even responding to a Trump tweet that attacked the media by saying: "The Kremlin doesn't need any troll factories as long as it has YOU trolling on behalf of it!"

In the two weeks that followed the February 8 email, the State Department continued to correspond with Aro and make preparations for her travel to the US, according to the Senate Democrats' report. On February 20, the embassy texted Aro to arrange a meeting two days later. In the meantime, the embassy's consular section confirmed with her that a visa interview would take place on February 25.

Aro told without an official explanation she wouldn't get award

But at her meeting on February 22, Aro was informed in person that she would not receive the award, the committee Democrat's report said. The embassy "did not provide any official or documented explanation."

Aro still went to the embassy on the day her visa interview was scheduled. She brought a letter from her lawyer seeking answers about the timing of the withdrawal, why it was not communicated sooner, and who made the decision. According to the Democrats' report and Aro, the State Department had not yet responded to the letter. Aro had canceled "several previously booked speaking engagements in Brussels and around Finland, including three lectures about countering the security threats posed by Russian trolls and fake news," according to the report.

The State Department had completed extensive preparations for Aro to be honored at the event on March 7 in Washington, according to the Senate committee's report.

The US Embassy in Helsinki had provided her with visa paperwork and flight option and a personalized itinerary for her visit to the US had been compiled, including a stop in Chicago with proposed visits to organizations like the Medill Justice Project, The Association for Women Journalists and The Chicago Tribune. It had been planned to focus on her "specific areas of work and themes of interest," according to the document.

The State Department had extended an invitation -- nontransferable with an official letter head -- on behalf of Pompeo requesting "the pleasure of your company at the 2019 International Women of Courage Awards."

The bio, which had been approved for her by eight State Department officials, said that Aro "has been a pioneer on this issue for several years and remains a testament to the effort against Russian disinformation."

It was listed on a page for "proposed awardees" -- all the other women listed received their awards.

"This setback with the award doesn't in any way hinder me from my work exposing Russian troll activities, techniques and impact on real people and real societies," Aro told CNN. "My work continues."