In one case, Trump’s personal attorney and a business associate exchanged emails weeks before the Republican National Convention about the lawyer possibly traveling to an economic conference in Russia that would be attended by top Russian financial and government leaders, including President Vladi­mir Putin, according to people familiar with the correspondence.

In the other case, the same Trump attorney, Michael Cohen, received a proposal in late 2015 for a Moscow residential project from a company founded by a billionaire who once served in the upper house of the Russian parliament, these people said. The previously unreported inquiry marks the second proposal for a Trump-branded Moscow project that was delivered to the company during the presidential campaign and has since come to light.