A new report from Politico highlights criticism from several Secret Service veterans targeting an upcoming anti-Hillary Clinton book from former Secret Service officer Gary J. Byrne. Those current and former Secret Service members argue Byrne “was too low-ranking” to have witnessed the gossipy events he details in the book and suggest he is lying for political and financial benefit.

Byrne’s Crisis of Character, which is set to be released next week, has received widespread promotion from conservative media outlets. Presumptive Republican presidential nominee Donald Trump has plugged the book several times on Twitter, claiming it shows Clinton does not have the temperament to be president. Trump also referenced the book during a June 21 Fox & Friends appearance, saying “her Secret Service agent” claims “she’s a total mess.”

Unsurprisingly, the Drudge Report, which has repeatedly promoted allegations from Crisis of Character, reports that Byrne will give his first TV interview promoting the book on Sean Hannity’s Fox News show (Hannity has already pushed the book, including during an interview earlier this month with Trump).

In contrast to the widespread praise from Trump and right-wing media outlets, Secret Service veterans think Byrne’s book is not credible. In a June 21 article, Politico reports complaints about the book from “several high-level members of Secret Service presidential details,” who say Byrne is “inflating his role,” relaying unverified gossip, and making “security harder by eroding the trust between agents and the people they protect.”

The nonpartisan Association of Former Agents of the United States Secret Service (AFAUSSS) will reportedly release a statement ripping the book, which Politico says “very carefully calls Byrne a liar.”