According to the New York Times Ukrainian hacker under the nickname Profexer is the developer of the program P. A. S., which was hacked the servers of the US democratic party. He surrendered to the Ukrainian police and now spoke to the FBI as a witness.
He said he created the program not to hack American servers and sell it to some customers and helped to use. He knows only the aliases of buyers online.
The paper also notes that evidence that a hacker was working for the Russian secret services is not found.