Donald Trump Jr. | KERA News

Donald Trump Jr.

Updated at 11:23 a.m. ET

When Donald Trump Jr. met with Russian lawyer Natalia Veselnitskaya last June at Trump Tower to gather information on Hillary Clinton for his father's presidential campaign, it's now clear there was at least one more Russian in the room. He has been identified in published reports as a Russian-American lobbyist named Rinat Akhmetshin.

Updated 5:30 p.m. ET

Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, tells NPR that he's sending a letter to Donald Trump Jr., saying that he wants the president's eldest son to testify in an open session of the committee and will subpoena him if necessary.

Grassley first spoke with CNN.

It's the first formal invitation for Trump Jr. to appear before congressional investigators, who want to learn more about his June 2016 meeting with Russian lawyer Natalia Veselnitskaya.

The headlines get more breathless by the moment. "Explosive new charges!" "A bombshell!"

Was it a crime for Donald Trump Jr. to meet with a Russian government-connected lawyer who promised dirt on Hillary Clinton for use in the presidential campaign? Was it worse than a crime? Was it treason?

The latest Russian caper — this one involving the president's son, then-Trump campaign chairman Paul Manafort and the president's son-in-law Jared Kushner — has Washington (pardon the pun) atwitter.

Donald Trump, Jr. tweeted images of emails regarding his 2016 meeting with a Russian lawyer on Tuesday. An intermediary said he could connect Trump Jr. with people who had information "that would incriminate Hillary [Clinton]... and would be very useful to your father."

Updated at 5:41 p.m. ET

Donald Trump Jr. on Tuesday tweeted an email exchange that seemed to show the president's son entertained an offer of Russian government help for his father to be elected president in 2016.

"This is obviously very high level and sensitive information but is part of Russia and its government's support for Mr. Trump," said the text that Trump Jr. posted on Twitter.