Republican senator and Trump ally Lindsey Graham told a police officer badly beaten during the Capitol attack that law enforcement should have shot rioting Trump supporters in the head, according to a new book.

“You guys should have shot them all in the head,” the now ex-cop, Michael Fanone, says the South Carolina Republican told him at a meeting in May 2021, four months after the deadly attack on Congress.

“We gave you guys guns, and you should have used them. I don’t understand why that didn’t happen.”

On January 6, Fanone was a Metropolitan police officer who came to the aid of Capitol police as Trump supporters attacked. He was severely beaten, suffering a heart attack and a traumatic brain injury.

He has since resigned from the police, testified to the House January 6 committee and become a CNN analyst. His book, Hold the Line, will be published next week.

Politico reported the remarks Fanone says were made by Graham. The site also said Fanone secretly recorded other prominent Republicans, among them Kevin McCarthy, the House minority leader and possibly the next speaker, who has also stayed close to Trump.

Politico said Fanone told McCarthy efforts to minimize the Capitol insurrection were “not just shocking but disgraceful”. McCarthy reportedly offered no response.

Last week, Rolling Stone published an extraordinarily frank interview in which Fanone, a self-described lifelong Republican, called McCarthy a “fucking weasel bitch”. McCarthy did not comment.

According to Politico, Fanone told Graham he “appreciated the enthusiasm” the senator showed for shooting rioters “but noted the officers had rules governing the use of deadly force”.

Fanone says the meeting with Graham was also attended by Harry Dunn, a Capitol police officer who has also testified in Congress, and Gladys Sicknick and Sandra Garza, the mother and partner of Brian Sicknick, an officer who died after the riot.

Fanone says Graham snapped at Gladys Sicknick, telling the bereaved mother he would “end the meeting right now” if she said more negative things about Trump.

Nine deaths, including officer suicides, have been linked to the Capitol attack. The riot erupted after Trump told supporters to “fight like hell” to overturn his defeat by Joe Biden, which he maintains without evidence was the result of electoral fraud. Rudy Giuliani, Trump’s attorney, urged Trump’s supporters to stage “trial by combat”.

Testimony to the House January 6 committee has shown Trump knew elements of the crowd were armed but told them to march on the Capitol and tried to go with them.

Representatives for Graham did not comment to Politico. The senator was previously reported to have advocated the use of force against Capitol rioters on the day itself.

That same day, Graham seemed to abandon his closeness to Trump. In a Senate speech hours after the Capitol was cleared, he said: “Count me out.” Days later, he said he had “never been so humiliated and embarrassed for the country”.

But like most Republicans, McCarthy literally so, Graham returned to Trump’s side. Like all but seven Republican senators, Graham voted to acquit in Trump’s second impeachment trial, for inciting the Capitol attack.

He recently predicted “riots in the streets” if Trump is indicted for retaining classified documents after leaving the White House.

In their recent book, The Divider: Trump in the White House, 2017-2021, Peter Baker of the New York Times and Susan Glasser of the New Yorker quote Graham as calling Trump “a lying motherfucker” … but “a lot of fun to hang out with”.