Alexander Nix, who heads a controversial data-analytics firm that worked for President Donald Trump’s campaign, wrote in an email last year that he reached out to WikiLeaks founder Julian Assange about Hillary Clinton’s missing 33,000 emails.

Nix, who heads Cambridge Analytica, told a third party that he reached out to Assange about his firm somehow helping the WikiLeaks editor release Clinton’s missing emails, according to two sources familiar with a congressional investigation into interactions between Trump associates and the Kremlin. Those sources also relayed that, according to Nix’s email, Assange told the Cambridge Analytica CEO that he didn’t want his help, and preferred to do the work on his own.