Timeline: Hunter Biden under legal, political scrutiny

Five years into a federal probe of his personal and professional life, President Joe Biden's son, Hunter Biden, is facing additional legal exposure in the coming months after a summer punctuated by setbacks.

U.S. Attorney David Weiss, a Trump-era appointee who has since been elevated to special counsel, has indicted the younger Biden on felony gun charges after a plea deal between the two parties fell apart in a Delaware courtroom in July.

Meanwhile, on Capitol Hill, House Speaker Kevin McCarthy this week said he would initiate an impeachment inquiry against President Biden over his alleged role in his son's influence-peddling, despite a dearth of concrete evidence.

Here's a timeline of Hunter Biden's legal and political scrutiny.

Dec. 10, 2020

A month after Joe Biden wins the 2020 presidential election, Hunter Biden announces that federal prosecutors in Delaware are investigating his "tax affairs."

A source with knowledge of the investigation tells ABC News that the tax probe began in 2018, but that the U.S. attorney's office in Delaware waited to notify Hunter Biden's legal team due to sensitivities around the election.

Investigators are looking into Hunter's business dealings in China and elsewhere, including scrutinizing whether he may have committed tax crimes stemming from those overseas business dealings, sources tell ABC News.

Dec. 21, 2020

Outgoing Attorney General William Barr says he doesn't intend to appoint a special counsel to investigate Hunter Biden, as President Donald Trump and others have suggested.

April 2, 2021

In a new memoir, Hunter Biden addresses many of the topics that emerged as fodder for his father's political foes during the presidential campaign, including his struggles with substance addiction, his dealings in China, and his seat on the board of a Ukrainian oil and gas firm during his father's tenure as vice president -- a role that later led to then-President Donald Trump's first impeachment trial on charges that Trump pressured Ukrainian President Volodymyr Zelenskiy to investigate Hunter Biden's position on the board. Trump was subsequently acquitted.

The memoir, titled "Beautiful Things," also offers lurid details as it chronicles the younger Biden's repeated relapses into drug and alcohol abuse.

March 30, 2022

ABC News reports that the federal investigation into Hunter Biden over his tax affairs has intensified, according to sources.

Sources say a number of witnesses have appeared before a grand jury Wilmington, Delaware, in recent months, and have been asked about payments Hunter Biden received while serving on the board of directors of Ukrainian natural gas company Burisma, as well as about how he paid off tax obligations in recent years.

Nov. 17, 2022

Fresh off the GOP regaining control of the Senate in the midterm elections, congressional Republicans say they're poised to push ahead with an investigation into President Joe Biden's family, including Hunter Biden, in the coming session.

Reps. Jim Jordan of Ohio and James Comer of Kentucky, two high-ranking members expected to helm powerful committees when Republicans take control of Congress in January, pledge to "pursue all avenues" of wrongdoing, calling investigations into the president's family a "top priority."

Dec. 21, 2022

Ahead of an expected deluge of Republican probes, Hunter Biden retains high-powered defense lawyer Abbe Lowell to help navigate congressional oversight.

March 1, 2023

Testifying in his annual oversight hearing before the Senate Judiciary Committee, Attorney General Merrick Garland says that U.S. Attorney David Weiss has been told he has "full authority" to make any charging decisions stemming from the Hunter Biden investigation, even if that would involve bringing a case in a district outside of Delaware.

Garland also says he has pledged to Weiss any resources necessary to conduct his investigation, and has received no reports thus far of the his investigation being stymied in any way by personnel at the main Justice Department.

March 17, 2023

Attorneys for Hunter Biden file counterclaims alleging invasion of privacy in response to a defamation lawsuit brought by Delaware-based computer repairman John Paul Mac Isaac, who they say triggered the infamous laptop controversy in the weeks leading up to the 2020 presidential election.

The counterclaim is in response to an ongoing defamation lawsuit against Hunter Biden and others that was filed in October 2019 by Mac Isaac, who Hunter Biden's attorney say obtained and later disseminated data from a laptop allegedly belonging to the younger Biden.

April 20, 2023

ABC News reports that a supervisor at the IRS has told lawmakers that he has information that suggests the Biden administration could be mishandling the investigation into Hunter Biden, according to sources.

In a letter to lawmakers obtained by ABC News, the lawyer for the IRS whistleblower says his client is an IRS criminal supervisory special agent "who has been overseeing the ongoing and sensitive investigation of a high-profile, controversial subject since early 2020 and would like to make protected whistleblower disclosures to Congress."

The letter says that "The protected disclosures: (1) contradict sworn testimony to Congress by a senior political appointee, (2) involve failure to mitigate clear conflicts of interest in the ultimate disposition of the case, and (3) detail examples of preferential treatment and politics improperly infecting decisions and protocols that would normally be followed by career law enforcement professionals in similar circumstances if the subject were not politically connected."

May 3, 2023

ABC News reports that the GOP-led House Oversight Committee has issued a subpoena demanding the FBI produce a record related to an alleged "criminal scheme involving then-Vice President Joe Biden and a foreign national."

The subpoena seeks an unclassified FD-1023 document, which is generally defined as a report from an informant. The White House denounces the contents of the document as "anonymous innuendo."

May 16, 2023

Attorneys for the IRS whistleblower inform key members of Congress that their client -- along with his "entire investigative team" -- has been removed from the probe into the president's son. The Justice Department defers comment to U.S. Attorney David Weiss, who does not comment on the claim.

June 5, 2023

House Oversight Committee Chairman James Comer announces his intention to initiate contempt of Congress hearings over FBI Director Chris Wray's refusal to physically turn over the FD-1023 document that Republicans believe is related to President Joe Biden.

June 20, 2023

Hunter Biden agrees to plead guilty to a pair of tax-related misdemeanors and enter into a pretrial diversion agreement that would enable him to avoid prosecution on one felony gun charge, potentially ending the yearslong probe.

According to the agreement, the younger Biden will acknowledge his failure to pay taxes on income he received in 2017 and 2018, until they were paid in 2020 by a third party, identified by ABC News as attorney and confidant Kevin Morris. In exchange, prosecutors will recommend probation, meaning Hunter Biden will likely avoid prison time. For the gun charge, he will agree to pretrial diversion, with the charge being dropped if he adheres to certain terms.

June 21, 2023

U.S. Judge Maryellen Noreika sets a court date of July 26 for Hunter Biden to make his initial court appearance related to the plea deal he has agreed to.

June 22, 2023

The GOP-led House Ways and Means Committee releases transcripts of their interviews with two IRS whistleblowers that they say show that senior Biden administration officials stymied U.S. Attorney David Weiss' investigation into Hunter Biden. In their testimony, the whistleblowers claim that senior Justice Department officials blocked prosecutors' attempts to bring charges against Hunter Biden in Washington and California, and refused to grant Weiss special counsel status.

Justice Department officials dispute the claim, saying, "As both the Attorney General and U.S. Attorney David Weiss have said, U.S. Attorney Weiss has full authority over this matter, including responsibility for deciding where, when, and whether to file charges as he deems appropriate. He needs no further approval to do so."

June 23, 2023

ABC News reports that House Oversight Committee Chairman James Comer has been given access the redacted FD-1023 document that allegedly contains claims about what Comer calls a "criminal scheme involving then-Vice President Biden and a foreign national relating to the exchange of money for policy decisions." But Comer tells reporters that reading the document was "a total waste of my time," as more than half of the document was redacted. Rep. Jamie Raskin, the ranking Democrat on the Oversight panel, says the Trump-era Justice Department investigated the claims and, "in August 2020, Attorney General [William] Barr and his hand-picked U.S. Attorney signed off on closing the assessment."

Congressional Republicans have also seized on a July 2017 WhatsApp message in which the younger Biden purportedly threatened a Chinese business associate by invoking his father's political connections, allegedly writing, "I am sitting here with my father and we would like to understand why the commitment made has not been fulfilled. Tell the director that I would like to resolve this now before it gets out of hand, and now means tonight."

"And, Z, if I get a call or text from anyone involved in this other than you, Zhang, or the chairman, I will make certain that between the man sitting next to me and every person he knows and my ability to forever hold a grudge that you will regret not following my direction," the message continues. "I am sitting here waiting for the call with my father."

At the time of the message, Joe Biden's term as vice president had already ended and he held no political office. But Republicans say the message undercuts President Biden's claim that he never discussed overseas business endeavors with his son. Ian Sams, a White House spokesperson, reiterates that "the president was not in business with his son."

Meanwhile, Attorney General Merrick Garland disputes outright the IRS' whistleblowers' claim that Trump-appointed U.S. Attorney David Weiss had requested to be named a special counsel but was turned down, saying, "Mr. Weiss never made that request to me."

June 26, 2023

House Speaker Kevin McCarthy, regarding the IRS whistleblowers' claim that Garland turned down Weiss' request to be named a special counsel in the Hunter Biden probe, tells Fox News, "If it comes true what the IRS whistleblower is saying, we're going to start impeachment inquiries on the attorney general."

July 12, 2023

ABC News reports that Weiss has pushed back on the IRS whistleblowers' allegations, writing in a letter to Sen. Lindsey Graham of the Senate Judiciary Committee: "To clarify an apparent misperception and to avoid future confusion, I wish to make one point clear: in this case, I have not requested Special Counsel designation."

Separately, in an appearance before the House Judiciary Committee, FBI Director Christopher Wray is asked by Rep. Matt Gaetz, "Are you protecting the Bidens?"

"Absolutely not," Wray answers.

July 13, 2023

Hunter Biden's attorney Abbe Lowell sends a cease-and-desist letter to Trump's legal team claiming that Trump's rhetoric on social media and elsewhere "could lead to [Hunter Biden's] or his family's injury."

"This is not a false alarm," Lowell writes. "You should make clear to Mr. Trump -- if you have not done so already -- that Mr. Trump's words have caused harm in the past and threaten to do so again if he does not stop."

July 19, 2023

In congressional testimony, the two IRS whistleblowers -- 14-year IRS veteran Gary Shapley and IRS investigator Joseph Ziegler, who has previously been unidentified -- reiterate their claims that Justice Department officials stymied Weiss' probe of Hunter Biden.

"It appeared to me, based on what I experienced, that the U.S. Attorney in Delaware in our investigation was constantly hamstrung, limited and marginalized by DOJ officials," Ziegler says. "I still think that a special counsel is necessary for this investigation."

July 20, 2023

In an unusual move, Sen. Chuck Grassley, R-Iowa, releases the FD-1023 document containing a confidential FBI informant's unverified claim that, years ago, the Biden family "pushed" a Ukrainian oligarch to pay them millions of dollars.

The document cites an unnamed source who says that in 2015, Mykola Zlochevsky, the chief executive of Burisma -- the Ukrainian energy firm that hired Hunter Biden as a board member in 2013 -- claimed that he was "forced" to pay Joe and Hunter Biden $5 million each, apparently in exchange for orchestrating the firing of a Ukrainian prosecutor named Viktor Shokin who was purportedly investigating Burisma at the time.

The assertion that the elder Biden, who was then vice president, acted to have Shokin removed in an effort to protect Burisma has been undercut by widespread criticism of the former Ukrainian prosecutor that led the U.S. State Department itself to seek Shokin's ouster.

A White House spokesperson, responding to the document's release, says "congressional Republicans, in their eagerness to go after President Biden regardless of the truth, continue to push claims that have been debunked for years."

July 24. 2023

Under questioning from reporters, White House spokesperson Karine Jean-Pierre reiterates that President Biden "was never in business with his son."

July 26, 2023

Hunter Biden appears before U.S. Judge Maryellen Noreika to formally agree to the plea deal negotiated in June -- but during a contentious hearing, Judge Noreika defers the deal after taking issue with the structure of the arrangement.

Noreika requests additional briefings from the parties before she'll determine next steps. In the meantime, Hunter Biden enters a plea of not guilty.

July 31, 2023

Former Hunter Biden associate Devon Archer testifies before the House Oversight panel, telling legislators that Burisma, through Hunter Biden, benefitted by its association with the so-called "Biden brand" -- but that Hunter Biden only provided the "illusion of access" to his father and did not discuss his business dealings with him, according to committee members who participated in the closed-door hearing.

Aug. 3, 2023

House Republicans release the complete transcript of Devon Archer's testimony before the Oversight panel, which include his recollection that Hunter Biden put his father on speakerphone or referenced his father being on the phone in front of business associates "maybe 20 times" in the 10 years that Archer and Hunter Biden were business associates -- which included a period when Biden was vice president -- but that Joe Biden's interactions with Hunter Biden's associates were "not related to commercial business" and that Joe Biden had no involvement with Burisma or took any actions to benefit Burisma or Hunter Biden, according to the fully transcribed interview with the committee.

Archer confirms that he was not aware of any wrongdoing by President Biden, according to the transcription.

Aug. 11, 2023

Attorney General Merrick Garland appoints Delaware U.S. Attorney David Weiss as special counsel in his investigation of Hunter Biden, after the Trump appointee asked Garland to be appointed special counsel in the case.

Weiss says in court documents filed within minutes of his appointment that plea negotiations have reached "an impasse" and that he intends to drop the misdemeanor tax charges against Hunter Biden in Delaware and instead bring them in California and Washington, D.C., where prosecutors say the alleged misconduct occurred.

Aug. 14, 2023

Attorneys for Hunter Biden say in a court filing that federal prosecutors reneged on the plea deal that would have resolved tax and gun charges against Hunter Biden.

Despite their acknowledgement that the plea agreement on tax charges is "moot," attorneys for Hunter Biden argue that the second part of the deal -- a diversion agreement on a separate gun charge -- remains in effect, since it is a separate contract negotiated and entered into by the parties outside the judge's purview.

Aug. 15, 2023

In court filings, prosecutors for Weiss push back on Hunter Biden's assertion that they "reneged" on the ill-fated plea deal, and dispute defense counsel's claim that the diversion agreement on a gun possession charge remains "valid and binding."

Sept. 6, 2023

Court documents filed by special counsel David Weiss say that Weiss intends to bring an indictment against Hunter Biden by the end of the month, pertaining to the felony gun charge that was previously brought under the pretrial diversion agreement brokered by the two parties.

Hunter Biden's legal team argues that the pretrial diversion agreement remains in effect.

"We believe the signed and filed diversion agreement remains valid and prevents any additional charges from being filed against Mr. Biden," says Abbe Lowell, an attorney for Hunter Biden. "We expect a fair resolution of the sprawling, 5-year investigation into Mr. Biden that was based on the evidence and the law, not outside political pressure."