IRS whistleblower speaks: DOJ "slow-walked" tax probe said to involve Hunter Biden

A whistleblower from inside the Internal Revenue Service has spoken publicly for the first time about a highly sensitive political probe he has supervised, which CBS News has determined is the ongoing probe into the finances of President Biden's son Hunter Biden. 

He said he became so concerned about prosecutors' handling of "a high profile, controversial" investigation that he felt duty-bound to sound alarms.

"There were multiple steps that were slow-walked — were just completely not done — at the direction of the Department of Justice," said Gary Shapley, a 14-year veteran of the agency, who spoke exclusively to CBS News chief investigative correspondent Jim Axelrod on Tuesday. "When I took control of this particular investigation, I immediately saw deviations from the normal process. It was way outside the norm of what I've experienced in the past."

The accusations come more than three years into an investigation into Hunter Biden that's being conducted in Delaware by a U.S. Attorney appointed by then-President Trump and held over by President Biden to avoid any appearance of political bias. The investigation focuses on potential crimes related to outstanding tax debts connected to income earned from a controversial stint as a board member for the Ukrainian energy company Burisma while his father was vice president, and a potential false statement related to a gun purchase. Last year CBS News reported that the past-due taxes were paid off with a loan from high-powered Hollywood attorney Kevin Morris, who provided Hunter Biden with financial backing.