Federal officials considered the purchase of a heat ray that makes targets' skin feel like it's burning and amassed thousands of rounds of ammunition in preparation for clearing a peaceful protest in Lafayette Square in June, according to written House testimony from an Army National Guard major who was at the scene, CNN reports.

Maj. Adam DeMarco described the preparations -- including officials' failure to acquire a loud announcement device for warning protesters to disperse -- in an August letter responding to follow-up questions after he testified before the House Committee on Natural Resources in June about federal officers' efforts earlier that month.

DeMarco, who says he was one of the senior National Guard officials on the scene, ran as a Democrat for Maryland's 3rd Congressional District in 2018.

DeMarco's letter says the Defense Department's head military police officer for the National Capitol Region emailed him and others on the day of the protests asking if the DC National Guard had "a Long Range Acoustic Device," a weapon that can blast walls of sound at protesters, or "the Active Denial Systems," which features "a directed energy beam that provides sensation of intense heat on the surface of the skin."

According to DeMarco's letter, he replied to the request with a no, saying the DC National Guard had neither device, and that to his knowledge, no such acoustic device was used at Lafayette Square. But the next day, when he looked into obtaining the acoustic device, the DC National Guard told him "that they were no longer seeking" it.

The letter goes on to say, the US Park Service's "warnings to disperse" did not come from that system but from "a red and white megaphone" that DeMarco observed officials using. During his in-person testimony, DeMarco referenced this, explaining that even 30 feet from the megaphone, the "warnings to disperse were barely audible and I was only able to discern several words." 

The Major also referenced a weapons transfer to the DC National Guard the afternoon of the protest that he says contained "approximately 7,000 rounds of ammunition."

During  his appearance before the committee in June, DeMarco testified that tear gas was used on protesters, saying, "I could feel irritation in my eyes and nose, and based on my previous exposure to tear gas in my training at West Point and later in my Army training, I recognized that irritation as effects consistent with CS or 'tear gas.' And later that evening, I found spent tear gas canisters on the street nearby."

Federal agents were widely criticized for using smoke canisters and rubber bullets to clear peaceful demonstrators who were in Lafayette Square protesting institutionalized racism and police brutality following the death of George Floyd at the hands of police.

A series of lawmakers and public figures spoke out against the move, among those who vocally criticized the response were former Defense Secretary James Mattis and Washington Mayor Muriel Bowser.

News of the contents of DeMarco's letter was first reported by NPR.