Donald Trump Jr. couldn't remember who was at the other end of a mystery 4-minute phone call - Mueller might have the answer

Jonathan Ernst/Reuters

Robert Mueller.

• People are zeroing in on a four-minute mystery call between Donald Trump Jr. and a blocked number.
• That discussion took place just days before a controversial June 2016 Trump Tower meeting between top Trump campaign officials and Russians.
• Special counsel Robert Mueller could uncover the identity of that caller, one expert said.
• Trump Jr. said he did not recall who the call was with, according to closed-door transcripts released Wednesday by the Senate Judiciary Committee.

There is a four-minute mystery phone call - which took place just prior to the June 2016 Trump Tower meeting between Trump campaign officials and Russians - that Donald Trump Jr. claimed he couldn't remember much of anything about.

Special counsel Robert Mueller, however, could have an easy time finding that information, one expert said in highlighting the mystery call.

That call gained attention Wednesday after the Senate Judiciary Committee released roughly 2,000 pages of documents stemming from closed-door interviews about the controversial Trump Tower meeting, which featured Trump Jr., the indicted campaign manager Paul Manafort, White House senior adviser Jared Kushner, Kremlin-connected lawyer Natalia Veselnitskaya, and others. 

The call took place just three days before the meeting, and happened in between a pair of calls to Emin Agalarov, the Russian pop star and businessman who is connected to President Donald Trump via the Miss Universe pageant he helped put on in Moscow in 2013.

Lawmakers asked Trump Jr. about the first call between Agalarov and Trump Jr., which took place at 4:04 p.m. ET on June 6, 2016. Trump Jr. said he had no recollection of what was discussed. Trump Jr. then had a call with a blocked number roughly 20 minutes later. Minutes after that call, he called Agalarov back. He said he had no recollection of who the call with the blocked number was with, and that he had no recollection of the second call with Agalarov.

Some online began to speculate that the blocked number may have belonged to the president.

As Matthew Miller, a former Justice Department spokesperson in President Barack Obama's administration, tweeted, Mueller could find out the identity of the caller if he sought it.

Once the meeting was reported publicly last summer, Trump reportedly helped formulate one of his eldest son's responses. Trump Jr. insisted in testimony that he did not discuss the meeting with his father, though Trump Jr. acknowledged that the president may have "commented through" former White House communications director Hope Hicks regarding that response, which The Washington Post reported last July that Trump was personally involved in drafting aboard Air Force One.

After the meeting was disclosed publicly last year, Trump Jr. initially said its purpose was to discuss Russian adoption policy. But the story began to shift in subsequent days, and Trump Jr. eventually released emails between him and Rob Goldstone, the British music publicist who helped coordinate the meeting with Veselnitskaya.

In the email exchange, Veselnitskaya was identified as a "Russian government attorney." Goldstone told Trump Jr. she wanted to share some information about Clinton as "part of Russia and its government's support for Mr. Trump."

Trump Jr. responded to Goldstone on the chain, "if it's what you say I love it especially later in the summer." 

But Veselnitskaya apparently did not ultimately provide damaging information on Clinton.