Christopher Steele’s dossier outlining allegations of collusion between the Trump campaign and Moscow occupied center stage during the Russia investigation.

Investigators are still digging into its origins.

But one new book reveals the source behind the dossier’s most explosive allegation.

The Steele dossier burst on the national scene because of the claim that Donald Trump had hired prostitutes to defile a bed that Barack and Michelle Obama slept in when they visited Moscow.

A “Source D” is named as the one who fed Steele this story—which is the reason why it was called the “Golden Showers” dossier.

And in the new book, “Russian Roullette: The Inside Story of Vladimir Putin’s War on America and the Election of Donald Trump,” journalists Michael Isikoff and David Corn identify Sergei Millian as “Source D.”

The Daily Caller reports:

“That’s according to “Russian Roullette: The Inside Story of Putin’s War on America and the Election of Donald Trump,” a book written by Michael Isikoff and David Corn that hit shelves on Tuesday.

The two veteran journalists report that Simpson told ABC News about Millian, the chairman of the Russian-American Chamber of Commerce, during the heart of the 2016 campaign.

ABC News reporter Brian Ross dutifully followed up on the lead, grilling Millian during the 2016 campaign about supposed contacts with Trump as well as to the Kremlin. 

 According to Isikoff and Corn, former British spy Christopher Steele revealed to Simpson that Millian was “Source D” for the dossier, which was funded by former Secretary of State Hillary Clinton’s campaign and the Democratic National Committee.

“Simpson would later learn from Steele the identity of Source D, the main source for the ‘golden showers’ allegation: It was Sergei Millian,” the book reads.

“Source D” is described in a June 20, 2016, memo written by Steele as “a close associate of TRUMP who had organized and managed his recent trips to Moscow.” The dossier claims that the source — now known as Millian — confirmed that the Kremlin had been feeding the Trump team intelligence on Clinton. 

 The information had been “very helpful” to the campaign, Millian said.”

This information – which even Fusion GPS co-founder Glenn Simpson did not believe was contained in the dossier – was what was used to gain a warrant to spy on former Trump campaign aide Carter Page.

It was clear from the beginning that including information like the Golden Showers episode meant the dossier had no credibility.

But because it was put together by a foreign spy, it was given the illusion of being an intelligence document.

Nevertheless, as more information is revealed about the dossier and the origins of the information it contained, it is obvious the real scandal was that it was used by the FBI and Obama administration to try and swing a Presidential election and then destroy a Presidency.