"Sater—who once had an office at New York’s Trump Tower, Trump Organization business cards, and claims to have worked as a senior adviser to Trump—has recently emerged as a key figure in the federal investigation led by special counsel Robert Mueller into Russian meddling in the 2016 presidential election. In the lead-up to the election, Sater worked extensively with Trump attorney Michael Cohen in a failed effort to build a Trump Tower in Moscow with the aid of Russian leader Vladimir Putin, which Sater said would help Trump win the presidency. According to statements made by Cohen last year, Trump personally signed-off on the project. Sater and Cohen also collaborated on a proposal early in the Trump administration to resolve the years-long conflict in Ukraine’s Crimea region, and to lift sanctions imposed against Russia for their military intervention in and annexation of the region. According to a recent BBC report, Sater even helped Cohen facilitate a meeting between Trump and Ukrainian leader Petro Poroshenko, for which Cohen was secretly paid $400,000. Sater and Cohen both denied that report."

I neither researched nor second sourced the extended-quote headline, but it is so excerpted without its five Daily Beast embedded links; story and links, here.