Mayor Daniel Biss of Evanston IL is opening two investigations after federal agents were filmed pinning down and repeatedly striking a person in the head as they arrested him Friday. DHS said the agents were conducting an immigration enforcement operation at the time. It said agents had observed a "red vehicle" that was "aggressively" tailing their vehicle, and when the agents turned, the car crashed into Border Patrol. DHS said a "hostile crowd" gathered around their vehicle and began "verbally abusing them and spitting on them." Mayor Biss disputed DHS' account of the incident, calling them "a bunch of liars." He is opening two investigations into the incident: one into the "violence" federal agents used against people he described as "innocent bystanders," and one into the vehicle collision. The Border Patrol agents "deliberately caused a car accident" by intentionally braking while being followed by the red vehicle, he said.