The story begins in the spring of 2014, following the Mayan Revolution that overthrew Ukraine's Russian-friendly President Viktor Yanukovych and replaced his government with a more Western-oriented regime.

Joe Biden, then Barack Obama's vice president, is tasked with supporting the new government and making frequent trips to Ukraine. In the same vein, his son Hunter Biden is offered a board position in Burisma Holdings, the country's largest private gas company.

Already then questions were raised about whether there could be a conflict of interest, but Joe Biden replied that he followed all ethical rules of the game and that his son is a private citizen who makes his own decisions, US public service company NPR writes.

Tasks: Received $ 50,000 a month

There are no concrete suspicions that any of them would have abused their position.

According to media reports, Hunter Biden received up to $ 50,000 a month for his board work. The role he played on the board is unclear. According to Dagens Nyheter, it was probably all about cleaning up the company's facade. He resigned in April this year when his five-year term ended.

Joe Biden played an active role when then-Prosecutor Viktor Sjokin was forced to leave his post in March 2016 after less than 14 months on his post. Sjokin was then accused from several quarters of contributing to corruption in the country, and both the United States and the International Monetary Fund (IMF) threatened to freeze their lending to Ukraine unless Sjokin resigned. This incident is the basis for Trump's claim that Biden intervened to protect his son.