Earlier this week, shocking footage showed a medical helicopter hovering dangerously close to protesters in Washington, D.C. in a maneuver that aviators described as a “show of force.” On Tuesday, Major Gen. William J. Walker, commanding general of the District of Columbia National Guard, announced that he’s opened an investigation into the incident. According to DCist, Walker’s office said he has “directed an investigation into a June 1 low-flying maneuver conducted by one of our rotary aviation assets.” The investigation will focus on the medical evacuation helicopter which was filmed hovering above protesters—a Black Hawk helicopter was also spotted performing a similar maneuver. Military justice experts condemned the use of the medical helicopter. “This was a foolish move,” Geoffrey Corn, a former Army lawyer told The Washington Post. “The symbolic significance of the Red Cross is pervasive: It denotes a ‘noncombatant’ function of the armed forces.”