Federal prosecutors have considered charging Hunter Biden with three tax crimes and a charge related to a gun purchase, said two sources familiar with the matter. The possible charges are two misdemeanor counts for failure to file taxes, a single felony count of tax evasion related to a business expense for one year of taxes, and the gun charge, also a potential felony. Two senior law enforcement sources told NBC News about "growing frustration" inside the FBI because investigators finished the bulk of their work on the case about a year ago. A senior law enforcement source said the IRS...