(CNN) Senate investigators have obtained new information showing Donald Trump Jr.'s mysterious phone calls ahead of the 2016 Trump Tower meeting were not with his father, three sources with knowledge of the matter told CNN.

Records provided to the Senate Intelligence Committee show the calls were between Trump Jr. and two of his business associates, the sources said, and appear to contradict Democrats' long-held suspicions that the blocked number was from then-candidate Donald Trump.

Later Thursday, ABC News and The New York Times reported the two associates were Nascar CEO Brian France and businessman Howard Lorber, who are both known associates of Trump. CNN has reached out to both for comment and they have not responded.

The information came to light recently and could answer one of the key questions over the meeting Trump's eldest son set up to get Russian dirt on the Clinton campaign. Trump Jr.'s phone calls involving blocked numbers -- meaning the numbers are private and do not appear in the phone records -- have been a lingering issue as investigators have probed the meeting and whether Trump himself had advance knowledge through any means that his son, son-in-law Jared Kushner and then-campaign chair Paul Manafort met with a Russian lawyer promising dirt on Hillary Clinton.

Trump Jr.'s phone records included calls with two blocked phone numbers the same day he exchanged calls with Russian pop star Emin Agalarov, the son of a Russian oligarch who spearheaded the June 2016 Trump Tower meeting with Russian lawyer Natalia Veselnitskaya. The calls came three days before the Trump Tower meeting, and an additional call with a private number occurred several hours after the meeting.

CNN has not confirmed what was discussed on the calls with the business associates. The purpose of the calls and their relevance to the Trump Tower meeting and the Russia investigation is still unclear. Trump Jr. attorney Alan Futerfas declined to comment.

The Senate Intelligence Committee's two-year investigation into 2016 Russian election interference is still ongoing and it's unknown whether the committee is still investigating the Trump Tower matter. Senate Intelligence Chairman Richard Burr, a North Carolina Republican, and Virginia Sen. Mark Warner, the top Democrat on the panel, both declined to comment.

It's not evident whether special counsel Robert Mueller has also obtained the phone records disclosing the identity of the private numbers, but the Trump Organization has provided both Mueller and Congress with a range of Russia-related documents.

The documents showing the calls were not with then-candidate Trump could resolve a key line of inquiry that House Democrats have said they want to get to the bottom of this year now that they are the majority party and have control of investigations.

The June 2016 Trump Tower meeting was hatched when Agalarov asked British promoter Rob Goldstone to arrange a meeting between Veselnitskaya and campaign officials. In an email to Trump Jr., Goldstone said that Veselnitskaya would provide "dirt" on Clinton at the meeting. "If it's what you say I love it," Trump Jr. responded, though when the meeting occurred on June 9, 2016, Veselnitskaya focused her presentation on Russian sanctions, and not Clinton dirt.

All of the participants in the meeting have spoken with one or all of the three congressional committees that have probed the meeting.

Democratic lawmakers have zeroed in on Trump Jr.'s four-minute call that occurred between the two calls he exchanged with Agalarov on June 6, 2016, three days before the Trump Tower meeting. Trump Jr. then had an 11-minute call with a private number that same evening, and also another a three-minute call with a blocked number two hours after the meeting.

Trump Jr. told congressional investigators in 2017 that he did not know who the blocked calls were with. When asked if he told his father about the meeting or the underlying offer of dirt on Clinton, he told the Senate Judiciary Committee : "No, I did not."

House Intelligence Chairman Adam Schiff, a California Democrat, has slammed his House Republican counterparts for not following through to obtain phone records to determine to whom Trump Jr. had spoken, writing last year that "the committee has not pursued leads to determine who called Trump Jr. at this crucial time from a blocked number." He's pledged to make it one of his first priorities as chairman.

In a 2018 memo outlining the areas of the Russia investigation that went unexplored, Schiff wrote that "(b)ased on the timing of these calls, the committee must determine whether some of these calls may be between Trump Jr. and Donald J. Trump, including calls concerning the Trump Tower meeting."

"We wanted to get the phone records to determine, was Donald Trump talking to his son about this meeting," Schiff told CNN in November. "It's an obvious investigative step, but one the Republicans were unwilling to take because they were afraid of where the evidence might lead."

Schiff declined to comment through a spokesperson for this story.

California Sen. Dianne Feinstein, the top Democrat on the Senate Judiciary Committee, also highlighted the blocked numbers i n a Democratic report last year on that panel's probe of the Trump Tower meeting. "We also do not know who they told about this meeting, including whether they ever discussed it with Mr. Trump," Feinstein wrote.

In her report, Feinstein wrote that Trump Jr. had placed the three calls to the blocked numbers. But Schiff's report in fact states that the first June 6 call was incoming to Trump Jr. A source familiar with the records provided to Congress said they did not indicate if the blocked calls were incoming or outgoing.

Democrats had reason to suspect the private number was Trump, as Trump's first campaign manager Corey Lewandowski told the committee that Trump's "primary residence has a blocked (phone) line," according to a report from Democrats on the House Intelligence panel.

In addition to the phone calls, Schiff has called for a subpoena to Trump Jr. to compel him to discuss the conversations he had with his father in 2017 about the 2016 Trump Tower meeting before Trump Jr. released a misleading public statement about the purpose of the meeting. Trump Jr. has claimed the conversations with his father were protected by attorney-client privilege when he testified in December 2017

In July, Agalarov told Vice News he had remembered speaking with Donald Trump Jr.

"I said, 'Listen, there's some people that want to meet you.' They obviously want something that could potentially help them resolve things that you could be interested in or maybe not. If you can spare a few minutes of your time, I'd be grateful. If not, no problem. Obviously Don Jr. obviously being Don Jr. said, 'Of course. I'll do it if you're asking,'" Agalarov told Vice.