A Defense Department official briefed on the matter downplayed DeMarco’s allegations, saying emails asking about specific weaponry were routine inventory checks to determine what equipment was available…

Just before noon on June 1, the Defense Department’s top military police officer in the Washington region sent an email to officers in the D.C. National Guard. It asked whether the unit had a Long Range Acoustic Device, also known as an LRAD, or a microwave-like weapon called the Active Denial System, which was designed by the military to make people feel like their skin is burning when in range of its invisible rays.

The technology, also called a “heat ray,” was developed to disperse large crowds in the early 2000s but was shelved amid concerns about its effectiveness, safety and the ethics of using it on human beings.

Pentagon officials were reluctant to use the device in Iraq. In late 2018, the New York Times reported, the Trump administration had weighed using the device on migrants at the U.S.-Mexico border — an idea shot down by Kirstjen Nielsen, then the Homeland Security secretary, citing humanitarian concerns.