Marc Kasowitz, a New York lawyer who has frequently worked for Trump over the years, recently signed on to defend U.S.-based business partners of Ihor Kolomoisky, the Bloomberg reports according to a court filing.

Kasowitz is representing Kolomoisky's co-defendants against civil claims in the U.S. that they stole billions of dollars from a Ukrainian bank and used the money to buy office buildings and businesses in the U.S, the agency said.

It also says that Kolomoisky is also under investigation by the FBI and federal prosecutors.