Former President Donald Trump's personal attorney Rudy Giuliani reportedly moved into Trump's Mar-a-Lago estate after losing his 2008 Republican presidential bid and used a tunnel under the Palm Beach home to travel back and forth unseen.

The revelation comes per Giuliani: The Rise and Tragic Fall of America's Mayor, a new book by journalist Andrew Kirtzman, who has covered Giuliani for three decades as a political reporter for print and television.

Kirtzman writes that Giuliani "dreamed of becoming president from a young age, [but] blew his big moment when it arrived." His loss upset him so much that he would drink considerably to "dull the pain."

Shortly thereafter, Trump allowed the Giulianis to stay in a bungalow across the street from Mar-a-Lago that could be accessed via an underground tunnel located beneath South Ocean Boulevard so they could avoid the media frenzy following Giuliani's loss.

Judith Giuliani reportedly told Kirtzman that her then-husband fell into "a clinical depression" but that they "moved into Mar-a-Lago and Donald kept our secret."

The relationship between the two men deepened, and it is perhaps this dark period that, at least in part, motivated Giuliani to back Trump's future lies about the integrity of the 2020 general election.

Kirtzman writes:

"What's clear is the two men's friendship survived when a hundred other Trump relationships died away like so many marriages of convenience."

"Giuliani would never turn his back on Trump, much to his detriment."

The new details about the Trump-Giuliani relationship began to circulate after The Guardianobtained an advance copy of the book, which will be published next month. Giuliani has never discussed this period of his life, only tellingThe New York Times in 2018 that he “spent a month at Mar-a-Lago, relaxing” after the primary a decade before.

They also come shortly after agents with the Federal Bureau of Investigation (FBI) combed through Trump's home turned paid membership resort on a hunt for documents Trump took from the White House in violation of federal laws and presidential protocol.

According to the FBI, Trump had about 20 boxes in his possession, including 11 sets marked as top secret or sensitive, comprising a total of over 300 documents.

The latest information about Giuliani has only increased the scrutiny that he and Trump have been under in the weeks since the search.

Giuliani has long denied that he has a drinking problem.

Earlier this summer, Giuliani went after Trump campaign manager Bill Stepien and communications strategist Jason Miller, both of whom said he was visibly intoxicated on Election Night as Trump and his team waited for the results to roll in.

Stepien and Miller made their claims under oath in their testimony before the House Select Committee tasked with investigating the events of January 6, 2021—the day a mob of Trump's supporters including known White nationalist and White supremacist groups attacked the United States Capitol on the false premise the 2020 general election was stolen.

Miller said Giuliani, a former Republican Mayor of New York City, "was definitely intoxicated." Miller also claimed to recommend Trump not declare victory despite initially enjoying a lead over Democrat Joe Biden in crucial battleground states.

The testimony from the two Trump campaign insiders prompted Wyoming Republican Representative Liz Cheney—January 6 House select committee vice chair—to criticize Trump by suggesting he listened to "an apparently inebriated Rudy Giuliani" instead of the guidance of his campaign advisors following the 2020 general election.

In outlining upcoming testimony during the ongoing hearings, Cheney said Trump likely followed Giuliani's advice "to just claim he won and insist that the vote counting stop, to falsely claim everything was fraudulent."