(CNN) Special counsel Robert Mueller is in talks with the attorney for the British publicist who set up the 2016 Trump Tower meeting between Donald Trump Jr. and a Russian lawyer, according to a source familiar with the matter.

Investigators want the publicist, Rob Goldstone , to come to the US to talk to the special counsel's team. No date has been picked yet, according to the source. The source said Goldstone has been invited to give a voluntary interview and has not been subpoenaed.

When asked for comment, Goldstone attorney Robert Gage told CNN on Friday that "nothing is presently scheduled with Mueller."

Goldstone's email also said that the information being offered was "part of Russia and its government's support for Mr. Trump." Four months later, the US intelligence community first publicly declared that Russia was meddling in the election. It wasn't until January 2017 that the intelligence community said the Russians specifically tried to help Trump.

Trump Jr. has said Veselnitskaya started the meeting by talking about how "individuals connected to Russia" had allegedly donated to the Clinton campaign, but that she provided no details to support her claims and then moved on to focus on the US sanctions under the Magnitsky Act, which aims to punish Russian officials responsible for the death of Russian lawyer Sergei Magnitsky, who died in a Russian prison, and the adoption of Russian children.

"To the extent they had information concerning the fitness, character or qualifications of a presidential candidate, I believed that I should at least hear them out," Trump Jr. said in a statement to the Senate Judiciary Committee.

Mueller's team has been in contact with some of the other people who attended the Trump Tower meeting, including Kushner, who has turned documents over to the special counsel's office. Another attendee, Russian-American lobbyist Rinat Akhmetshin, testified before Mueller's grand jury in August, the Financial Times reported . Akhmetshin worked with Veselnitskaya last year on a lobbying effort in the US to overturn the Magnitsky Act sanctions.

The Trump Tower meeting has also attracted the scrutiny of investigators on Capitol Hill. One of the other attendees, Russian-American businessman Ike Kaveladze, was interviewed by the House Intelligence Committee earlier this month.

NBC News reported about the discussions with Goldstone earlier on Friday.

A spokesman for the special counsel declined to comment.