The super PAC backing Robert F. Kennedy Jr. got another cash infusion from GOP megadonor Tim Mellon in April, according to the latest campaign finance report.

Mellon is the largest GOP donor this campaign cycle to date, and has now given the American Values 2024 super PAC backing Kennedy’s long-shot independent presidential bid $20 million.

His $5 million donation also made up the vast majority of the super PAC’s haul last month, which totaled $6.1 million. Another $1 million in April came from PAC co-founder Mark Gorton, who also co-founded Limewire.

Mellon is a longtime GOP donor who also gave $5 million to Make America Great Again Inc., the super PAC backing former President Donald Trump, last year. More recently, he gave $5 million in March to the Congressional Leadership Fund, a super PAC for GOP House candidates, as well as $4 million to The Sentinel Action Fund, a super PAC affiliated with the conservative Heritage Foundation.

The Wyoming billionaire is also releasing a memoir this summer with Skyhorse Publishing, the publishing house run by Tony Lyons, the co-founder of American Values 2024. Kennedy provided a blurb for the book’s cover, according to its Amazon presale page.

American Values also continued its financial relationship with Gavin de Becker, founder of the security firm by the same name — though not through a new contribution.

De Becker was refunded $2 million on April 25. The return was another transaction in the “bridge funding” arrangement between the donor and super PAC. De Becker has now donated $14 million to American Values 2024 and received $11.65 million back since the PAC started backing Kennedy’s White House bid. His net contribution is now $2.35 million.

The arrangement has drawn scrutiny from Kennedy’s rivals, and the Democratic National Committee filed a complaint with federal regulators about the consistent transfers of funds back to de Becker, alleging that the contributions function as loans.

The super PAC also spent a bit over $100,000 on social media ads and $31,500 on radio ads in April, the filing showed. American Values ended the month with $20.8 million in cash on hand.