Rep. Joaquin Castro, D-Texas, said that if a follow-up email correspondence after the 2016 Trump Tower meeting between the Trump campaign and Russian officials, first reported Thursday, is authenticated, then it is a "very disturbing" find and that "equally disturbing" revelations are likely in the near future.

CNN reported earlier in the day that congressional investigators discovered the emails and brought them up during Donald Trump Jr.'s private interview with the House Intelligence Committee on Wednesday.

The report said that the follow-up emails, from the British publicist who set up the summer meeting, Rob Goldstone, were sent to both a Russian participant in the meeting as well as senior Trump aide Dan Scavino, who did not attend the meeting and is now the White House director of social media.

Castro, who is a member of the intelligence panel, wouldn't confirm to anchor Wolf Blitzer the existence of the emails or if they were discussed during Trump Jr.'s testimony. He did concede that if "we assume the emails are authenticated then it's clear that there was an attempt to continue the conversation and perhaps to continue working together on a relationship between the Trump campaign and Russian agents in the 2016 elections."

"These emails are very disturbing," he added. "I expect in the coming weeks and months we'll see more things that are equally disturbing come to light."

Congressional investigators say Trump Jr. acknowledged, but refused to answer, questions Wednesday about the discussion he had with his father, President Trump, after emails about the setup for the meeting came to light. The discovery of the emails over the summer led to Trump Jr. becoming a focus of investigations into Russian interference in the 2016 election.

The meeting was predicated on the promise of dirt on Hillary Clinton, Trump's Democratic opponent in the 2016 election, though Trump Jr. and Goldstone assert those promises from Russian lawyer Natalia Veselnitskaya were never delivered upon and that Veselnitskaya used the meeting to talk about Russian sanctions.

The content of the follow-up emails in the CNN report include Goldstone pushing Scavino to convince then-candidate Trump to create a page on a Russian social networking website. That email notes that "Don and Paul" were on board. CNN said that was a reference to both Trump Jr. and former Trump campaign manager Paul Manafort, who also attended the meeting.

Another email reportedly sent to Goldstone's client, Russian singer Emin Agalarov, and Russian attorney Ike Kaveladze, who attended the Trump Tower meeting, included a story about Russian hacking of Democratic National Committee emails.

Sources told CNN that Trump Jr. did not recall any post-meeting emails or their contents during his testimony. Previously Trump Jr. had contended there was no discussion with the meeting's participants after it took place.