President Trump’s personal attorney Rudolph W. Giuliani and his former top adviser Stephen K. Bannon, who have attracted the scrutiny of U.S. authorities for their political dealings in recent months, helped make public private materials purported to belong to Democratic presidential nominee Joe Biden’s son in an attempt to swing support to the struggling incumbent.

The Washington Post was unable to verify the authenticity of the alleged emails and other correspondence that the New York Post published Wednesday and said had come from the younger Biden’s computer and hard drive.

Neither Giuliani nor Bannon responded to multiple requests to review the hard drive and other materials for verification, nor did they respond to phone calls and emails on Wednesday seeking interviews.

An attorney for Giuliani responded to an email on which he was copied to ask what outlet the reporter represented. There were no further replies.

The Fact Checker unravels what happened when Trump tried to force an investigation into the false rumor about then-Vice President Joe Biden and Ukraine. (The Washington Post)

The New York Post, which is owned by conservative media tycoon Rupert Murdoch, said its report was based on materials it said it heard about from Bannon and were provided by Giuliani. The material, which it described as a “massive trove of data” that included video, was the subject of several stories published Wednesday.

Since late last year, Giuliani has said, he has met multiple times with Ukrainian lawmaker Andriy Derkach. The U.S. Treasury imposed sanctions on Derkach in September for being an active Russian agent interfering in the 2020 campaign, which Derkach has denied. Bannon recently pleaded not guilty to federal money-laundering and fraud charges.

The report Wednesday did not markedly advance what is already known about Hunter Biden’s foreign business dealings, other than to suggest that at one point he gave Vadym Pozharskyi, a Ukrainian business colleague, “an opportunity” to meet his father. The Biden campaign said the vice president’s schedule indicated no such meeting.

“We have reviewed Joe Biden’s official schedules from the time and no meeting, as alleged by the New York Post, ever took place,” Biden campaign spokesman Andrew Bates said.

“The New York Post never asked the Biden campaign about the critical elements of this story,” he added. “They certainly never raised that Rudy Giuliani — whose discredited conspiracy theories and alliance with figures connected to Russian intelligence have been widely reported — claimed to have such materials.”

Hunter Biden’s attorney, George Mesires, told The Washington Post that “this purported meeting never happened.” Pozharskyi, who works for Burisma, the Ukrainian gas firm that included Hunter Biden on its board from 2014 to 2019, could not be reached for comment.

The leak of the materials less than three weeks before Election Day centered on some of the same unproven allegations against Biden that led to Trump’s impeachment late last year after he pressured Ukrainian authorities to investigate the former vice president.

Although reminiscent of the 2016 race — when Russian intelligence operatives hacked and released hundreds of emails from Democratic candidate Hillary Clinton’s campaign manager through WikiLeaks — Wednesday’s report was met with skepticism, particularly from social media companies that sought to limit the spread of the news.

Several intelligence experts also were skeptical of the report — and the stated origins of the hard drive purported to belong to Biden’s son — saying that it had the characteristics of a carefully planned information operation designed to affect an American election.

Thomas Rid, author of “Active Measures,” a book about disinformation, said hacking, forging and leaking information selectively are among the most effective disinformation methods, and raised suspicions about the material the New York Post published.

“Usually when emails are leaked, what investigators look for is the actual email file, and we don’t have that here,” Rid said, raising alarms that the emails do not include metadata, which can be used to verify the date, sender and recipient. When an email is presented without the metadata, he said, “then you become suspicious.”

John Paul MacIsaac, who said he owns a computer repair shop in Wilmington, Del., told The Post on Wednesday that the laptop in question was one of three damaged computers brought to his shop in April 2019. Repairing it required an involved process, he said, so he continued working on it using the password the customer provided.

He said he determined the data could be moved to an external hard drive and asked the customer to return and provide a hard drive, which he said the customer did. MacIsaac, who described himself as legally blind, said that he was almost certain the customer was Hunter Biden.

“I’m 99.9 percent sure it was him, but because of my visual impairments I’m not going to lie,” he said. “I can’t be 100 percent sure.”

MacIsaac said that he made several attempts to get in touch with Hunter Biden, but that after the equipment was still in his hands 90 days later, he became curious. (MacIsaac said his standard contract gives him possession of a device after 90 days.) MacIsaac said that he saw some of the contents, including what he described as multiple files, and contacted at least three members of Congress, whom he would not name. He also said that he contacted the FBI using an intermediary, whom he also would not name.

He said the agents initially told him they didn’t want to take possession of the hard drive and instead made a copy of it, but returned later in the year with a subpoena to take it.

Both the U.S. attorney’s office in Delaware and the FBI’s Baltimore field office declined to comment, citing the Justice Department’s practice of not confirming or denying investigations.

In late 2019, before he handed the equipment to the FBI, ­MacIsaac — who says he is fiscally conservative and socially liberal — made a copy of the contents of the hard drive. He grew frustrated that the contents of the laptop hadn’t become public, and over the summer he decided to contact Giuliani, who had been traveling to Ukraine and attempting to find compromising information about the Bidens.

Guiliani and Bannon have served as in-the-trenches foot soldiers for Trump, who regularly traffics in disinformation and falsehoods, since before his 2016 election.

Since at least early last year, Giuliani has attempted to drum up investigations of Biden and his son in both Ukraine and the United States, hoping to re-create an atmosphere of suspicion similar to that of 2016, when Clinton was dogged by investigations of her private email server.

Giuliani’s efforts in Ukraine led to impeachment proceedings in which Trump was charged with abuse of power and obstruction of Congress. The Republican-led Senate acquitted the president.

Giuliani’s interactions with the Ukrainian lawmaker Derkach, who studied at the Higher School of the KGB in Moscow, included meetings and Derkach speaking on a podcast hosted by the former New York mayor. In the months before the Treasury Department imposed sanctions on him, the lawmaker had been leaking edited tapes of then-Vice President Biden conducting diplomacy with Ukraine’s leadership, in an attempt to tarnish him.

One of Giuliani’s associates in his Ukraine gambit, Lev Parnas, was slapped with new federal charges last month of allegedly defrauding investors in a fraud-protection company he founded and for which Giuliani was paid a half-million dollars to consult.

Giuliani himself has been under investigation by the U.S. attorney’s office in Manhattan in that case, although prosecutors have not made any allegations against him and his attorney has sought to distance him from the matter.

Bannon, who served as chief executive of Trump’s 2016 campaign and later as senior counselor and chief strategist at the White House, was charged in August by federal prosecutors in New York, who alleged that he and three other men defrauded donors to a massive crowdfunding campaign that claimed to be raising money for the construction of a wall along the U.S.-Mexico border. He has pleaded not guilty.

Efforts to tarnish Hunter Biden and by extension his father have been a focus of Trump’s campaign over the past year and a half. The president and his allies have derided not only Hunter Biden’s business dealings, but also his struggles with substance abuse.

As recently as the Sept. 29 presidential debate, Trump ridiculed Hunter Biden, which led his father to make an emotional defense of his son that acknowledged his past drug addiction.

“My son, like a lot of people at home, had a drug problem,” Biden said. “He’s overtaken it. He’s fixed it. He’s worked on it. And I’m proud of him, I’m proud of my son.”

Biden has been adamant that he was unaware of his son’s business dealings and took no part in them, telling reporters in September 2019 that “I have never spoken to my son about his overseas business dealings.” He also pledged last year that his family would not engage in any foreign business activities if he is elected president.

Shane Harris, Ellen Nakashima, Josh Dawsey, Matt Zapotosky and Sean Sullivan contributed to this report.