An American-based employee of a Russian real estate company took part in a June 2016 Trump Tower meeting between a Russian lawyer and Donald Trump Jr., bringing to eight the number of known participants at the session that has emerged a key focus of the investigation of the Trump campaign’s interactions with Russian.

Ike Kaveladze’s presence was confirmed by Scott Balber, an attorney for Emin and Aras Agalarov, the Russian developers who hosted the Trump-owned Miss Universe pageant in 2013. Balber said Kaveladze works for the Agalarovs’ company and attended as their representative.

Balber said Tuesday that he received a phone call from a representative of Special Counsel Robert Mueller over the weekend requesting the identity of the Agalarov representative , which he said he provided. The request is the first public indication that Mueller’s team is investigating the meeting.