There’s an important follow-up to the IRS whistleblowers who exposed political interference in the Hunter Biden tax probe. Once facing retaliation for their disclosures, they’ve managed to turn the tables in a big way, vindicated with legal settlements and even promotions.

The drama began in 2018 when Joseph Ziegler, an IRS criminal investigator, uncovered potential tax fraud tied to the Bidens.

“You were seeing evidence that could potentially have implicated Joe Biden, Hunter's father, and were not allowed to follow that trail. Is that accurate?” "Full Measure" asked Ziegler in an interview.

“Yeah ...That’s just one example,” he replied. “There was talking to the family, Joe Biden's adult children: We were not allowed to do that. If there were any questions when we were doing interviews of certain people that led to Joe Biden, we weren't allowed to go and ask those questions.”

Ziegler says Justice Department and IRS bosses barred mention of Joe Biden in a Ukraine-related search warrant, tipped off Hunter’s attorney before a search warrant was executed, and blocked Ziegler from asking witnesses about a 2017 Hunter Biden email referring to "10% [of payments in a Chinese business deal] held by H [Hunter] for the big guy.” A former partner said the big guy was Joe Biden. The Bidens denied it. 

And Ziegler says the department blocked him from pursuing leads tying Joe Biden to alleged bribery involving Burisma. That’s the Ukrainian energy firm that paid Hunter millions.

“So it was very apparent from the beginning that they just didn't want to touch anything related to the former vice president at the time – wasn't even the President – Joe Biden,” he says. “So it was kind of like all hands off. And it just didn't seem appropriate. And looking back on everything, when you add it all in totality, it's a lot bigger of a deal than you might think. DOJ had this much control over essentially holding us down from doing a proper investigation related to the Biden family.”

Ziegler and his IRS supervisor, Gary Shapley, became whistleblowers. And in fall of 2024, the IRS moved to demote or force out Shapley. 

Whistleblowers rarely come out on top.

But with help from Congress and the whistleblower group Empower Oversight, Shapley and Ziegler pushed back. And the tide turned dramatically.

The IRS and Justice Department have settled retaliation claims with both men. The agreement reportedly requires mandatory training for prosecutors to prevent future misconduct. Two related lawsuits were also resolved favorably.

And Ziegler and Shapley not only kept their IRS jobs, they leveled up.

“We've also received promotions at the IRS,” Ziegler says. “Thank God for the secretary of Treasury – he made us senior advisers to him.”

After the whistleblowing, their work was vindicated when Hunter Biden pleaded guilty to nine tax offenses, charges Ziegler and Shapley originally sought.

But any leads allegedly pointing to Joe Biden appear to be forever dead, with time limitations on criminal filings expired.

In December 2024, on his way out the door of the White House, President Biden issued a sweeping presidential pardon for his son Hunter.

Now, Ziegler and Shapley have chronicled their odyssey in a book, "The Whistleblowers vs. the Big Guy.” Profits support future whistleblowers. 

For more on this story, watch "Full Measure with Sharyl Attkisson” Sunday. Attkisson's most recent book is "Follow the $cience: How Big Pharma Misleads, Obscures, and Prevails."