"Former Ukrainian General Prosecutor Viktor Shokin told Giuliani during a conversation in January 2019 that Ukraine stopped investigating Burisma Holdings, the Ukrainian gas company that placed Hunter Biden on its board in 2014, because of “fear of the United States.”
"The prosecutor also alleged that former Ukrainian president Petro Poroshenko told him to drop the case because it was “not in the interest of Joe and/or Hunter Biden.”
https://dailycaller.com/2019/10/02/ukraine-prosecutor-pressure-biden-giuliani-burisma/