In an interview Wednesday, President Trump once again brought up the debunked conspiracy theory suggesting that MSNBC commentator Joe Scarborough is a murderer.

The supposed victim was a female congressional aide who, investigators say, died in a fall caused by an undiagnosed heart ailment at then-Rep. Scarborough’s Florida office in 2001. Scarborough was in Washington at the time.

Yet on Wednesday, Trump told Fox News radio that he still thinks Scarborough “got away with murder.”

This may seem like a relatively recent development for Trump, who sees Scarborough and his wife and Morning Joe co-host Mika Brzezinski as political adversaries.

But in fact, he has been obsessing about it for years, and trying to convince Americans to believe it, reports the Daily Beast in an exclusive story.

Trump even had his son-in-law Jared Kushner press the supermarket tabloid National Enquirer to dig in to the baseless smear against Scarborough, the investigative website says.

“According to two people with direct knowledge of the matter, it was right around this time [mid-2017] that Trump started asking White House aides if he should tweet about “the dead girl”— as one of the people recalled the president phrasing it— to get back at … ‘Psycho Joe,’” the Beast says.

Advisers cautioned Trump not to do so, and he “remained mostly silent in public.”

But behind the scenes, the president was active, and — apparently under pressure — Kushner asked the Enquirer to pursue the story. 

“The Enquirer started working on a story at their behest,” a source with “direct knowledge of the situation” told The Beast.

The White House denies that Kushner spoke with either Trump or the Enquirer about Scarborough congressional staffer Lori Klausutis’s death 19 years ago.

In any event, Enquirer reporters failed to find “even threadbare proof” of the claim, despite the tabloid’s “notoriously low bar” for publication of such sensational stories.

“We reached out to experts and they dismissed theories that she’d met with foul play or Joe had anything to do with her death,” an unnamed source (who worked at the time for the Enquirer’s publisher) told the Beast.

Scarborough and Brzezinski have declined to comment, but they “have spoken privately with Twitter in recent weeks, imploring the company to remove Trump’s posts suggesting that the former congressman was somehow involved in his then-employee’s death,” the Beast says.