Rumors swirl that former Vice President Joe Biden will be a leading contender for the Democratic presidential nomination in 2020. Extremely early polls find strong support for him in his party. But investigative journalist and bestselling author Peter Schweizer has unearthed Biden’s history of corruption, and that will prove a major issue in the upcoming election.

“This is, I think, going to be a central issue” for 2020, Schweizer, best known for uncovering Hillary Clinton’s corruption but also the author of the new book “Secret Empires: How the American Political Class Hides Corruption and Enriches Family and Friends,” told Fox News’ Steve Hilton.

Schweizer’s book came out in March, but since then new evidence of the Biden family corruption has come to light. Schweizer told Hilton about a bank account unearthed in a New York conviction against Devon Hunter, a friend of the former vice president’s son, Hunter Biden.

“A bank account that Hunter Biden drew a lot of money from and that a lot of foreign entities put a lot of money into,” the author noted. “Just to give you an idea, over a 14-month period, from 2014 through early 2016, while Joe Biden is vice president of the United States, a Ukrainian company called Burisma — it’s controlled by a very corrupt oligarch — sends three million dollars into this account.”

“A Chinese government entity called Bohai Harvest — which is run by the Bank of China — sends $650,000 into this account,” Schweizer added. “There’s $1.2 million that comes from an LLC with a small boutique Swiss bank. We don’t know who’s behind the LLC. The bank itself has been charged in six countries for money laundering, so that makes it kind of sketchy.”

How does this connect to Joe Biden? Not only was the elder Biden vice president at the time, but he was directly involved with the countries his son struck deals with.

“If you look at the trajectory of Joe Biden as vice president, he was essentially U.S. point person on Chinese policy, and he was widely criticized for going very soft on them as it related to the South China Sea,” Schweizer said. “That’s at the same time his son is getting large checks from the Chinese government.”

“Joe Biden is also point person on U.S. policy towards Ukraine, at the same time that his son is getting large checks from the Ukrainian government. And he’s accused of looking the other way at fraudulent behavior and corruption with the government of Ukraine,” the author added.

Ouch.

Even so, all the money is only going to Hunter Biden, right? Why does this implicate his father?

“We’re all familiar with globalization and the phenomenon as it relates to the economy and corporations. Well, corruption is being globalized as well,” Schweizer pointed out. With a more and more globalized economy, U.S. policy has a direct impact on other countries.

Those countries “look for friends in Washington, and one of the best ways to make friends in Washington is to do deals with family members,” he explained.

He laid out how it works: “Joe Biden, every year he’s vice president, he has to disclose his income. Assuming those disclosures are honest, he can’t have a big fat check from the Chinese government in that disclosure form. But this adult son, Hunter Biden? He doesn’t have to disclose anything.”

Schweizer’s recent book is a must-read. The investigative journalist documented a great deal of corruption, but Joe Biden and Barack Obama came under the most scrutiny. Biden’s son Hunter and John Kerry’s stepson Chris Heinz both profited from their father’s soft policy towards China. Hunter Biden also reaped rewards from his father’s blind eye to Ukraine corruption. Obama’s policies enriched his best friend — and now head of the Obama Foundation — Marty Nesbitt.

Biden may pose a powerful threat to President Donald Trump in 2020. He appeals to many of the same blue-collar sentiments, and he has his own macho posturing against Trump. If Democrats choose Biden, however, they may face the same kind of fundamental weakness they experienced with Hillary Clinton. The skeletons in Biden’s closet may not be as bad as those in Hillary’s — but they are real, and very serious.

Peter Schweizer has the story, and he won’t stop telling it.

Follow the author of this article on Twitter at @Tyler2ONeil.