▶ Watch Video: Trump ramps up attacks against Ron DeSantis in Iowa

Former President Donald Trump and his allies have ratcheted up their attacks on potential rival Florida Governor DeSantis, whom Trump acknowledged to reporters earlier this week is “probably” his biggest challenger in the presidential primary.

A Trump source familiar with pro-Trump super PAC MAGA Inc.’s plans tells CBS News that it has been extensively reviewing DeSantis’ record as a Florida assistant U.S. attorney, congressman and governor. 

On Wednesday morning, MAGA Inc. filed a 15-page complaint with Florida’s Commission on Ethics that claimed DeSantis is running a “shadow presidential campaign” that violates state and federal election law. 

The Florida Commission on Ethics would not confirm nor deny receiving the complaint.

DeSantis is not in the 2024 presidential race yet, though in recent weeks, he’s traveled to promote his new book and his “Freedom Blueprint” in Iowa and Nevada, two early presidential primary states. He’ll also headline a Republican Party dinner in New Hampshire in April. 

In several private conversations with donors and allies, DeSantis has indicated he is leaning toward running and will make a final decision after his legislative session is over, according to two people familiar with his team’s private discussions.

Taylor Budowich, head of the Make America Great Again PAC, wrote in the complaint that DeSantis’ book tour and the ongoing fundraising of the allied “Friends of Ron DeSantis” state committee is unlawful and serves “his personal political objectives.” The two activities, Budowich continued, “are in furtherance of his personal financial gain at the expense of Florida taxpayers, and are intended to influence his official decision to resign from office.”

In a statement, DeSantis communications director Taryn Fenske said she’ll be adding this complaint “to the list of frivolous and politically motivated attacks,” and she countered that “it’s inappropriate to use state ethics complaints for partisan purposes.”

The complaint mentioned several groups aligned with or supporting DeSantis, including the newly formed “Never Back Down” super PAC, which is led by former Trump-era Department of Homeland Security official Ken Cuccinelli.

In reaction to the complaint, Cuccinelli taunted Trump campaign staff, writing, ” The overwhelming response we’ve received to building a DeSantis grassroots effort is exciting — and I’m sure intimidating. No wonder the folks on that campaign are nervous. They should be.”

“DeSantis leads the fight against the Woke Left, but Trump wants him removed from office because DeSantis’ book outsold Trump’s book,” Cuccinelli added. “In the words of President Trump: SAD!”