Thousands of pages of interview transcripts with the participants of the June 2016 Trump Tower meeting shed new light on how eager Donald Trump Jr. and senior members of the Trump campaign were to obtain damaging information on Hillary Clinton - and how frustrated and angry they were that the material did not come to fruition.
In an interview previous year with the Senate Judiciary Committee, Trump Jr. downplayed his father's role in the entire matter.
Mr Trump Jr deflected multiple questions during the interview, saying he could not recall whether he discussed the Russian Federation probe with his father and whether he spoke with Mr Trump on the day the meeting was arranged.
Trump Jr. said at the end of the 20-minute meeting that the adoption issue would be revisited if his father became president, Anatoli Samochornov, who served as translator at the meeting for Veselnitskaya, told the Senate committee staff.
Special Counsel Robert Mueller is also investigating.
In addition to Mr Trump Jr, the committee interviewed four other people who attended the Trump Tower meeting in NY - publicist Rob Goldstone, who set up the meeting with the promise of dirt on Mrs Clinton; Rinat Akhmetshin, a prominent Russian-American lobbyist; Ike Kaveladze, a business associate of a Moscow-based developer, and a translator.
Grassley had said in January he wanted to release the transcripts of the interviews.
The panel was also not able to interview Jared Kushner, Mr Trump's son-in-law, or Paul Manafort, Mr Trump's former campaign manager, even though both attended.
The committee's documents also included responses from Veselnitskaya, as well as a statement from Kushner and a page of notes from Manafort.
His notes mention "Russian adoption by American families" and Bill Browder, a British citizen who has spearheaded a US sanctions law -known as the Magnitsky Act- that targets Russian officials over human rights abuses.
Mueller has brought several unrelated charges against Manafort, including money-laundering conspiracy, false statements and acting as an unregistered foreign agent related to Ukrainian political work.
Last July, when the New York Times published a report about the meeting, a statement was crafted aboard Air Force One as the president returned from Germany.
Trump Jr. said that he neither offered his father advance warning that he'd been invited to learn about Russian government "dirt" on Clinton, or informed him after the fact that the conversation had instead mostly focused on reinstating a program allowing Americans to adopt Russian children. "Their efforts to hide the meeting and its true objective are consistent with a larger pattern of false statements about the Trump campaign's relationship with Russian Federation".
Kushner met behind closed doors for two hours with Senate investigators in late July 2017, telling reporters afterward of the handful of meetings he took with Russian officials, including at Trump Tower, "All of my actions were proper and occurred in the normal course of events of a very unique campaign", adding unequivocally, "I did not collude with Russians, nor do I know of anyone in the campaign who did". "I never spoke to my father about it".
The president's son said some of Trump's comments provided through Hicks may have been incorporated into the final statement.
"Jared Kushner, who is sitting next to me, appeared somewhat agitated by this and said, 'I really have no idea what you're talking about".