evidence: On Wednesday morning, Hunter Biden defied a congressional subpoena to testify behind closed doors to lawmakers. He told reporters at Capitol Hill he would only give evidence in a public setting and called Republican investigators "shameless". [...] An unverified tip to the FBI claimed Joe Biden pressured Ukraine's government to fire its top prosecutor to halt an investigation into the local Burisma energy firm, where Hunter Biden was on the board. [...] They pointed to a "sweetheart deal" reached between Hunter Biden and prosecutors earlier this year that would have seen him admit to criminal offences and avoid jail time.