An unmarked police vehicle was set ablaze Wednesday afternoon next to the Supreme Court, and a badly burned suspect was taken to the hospital.

A man poured an accelerant over an unmarked Supreme Court police vehicle parked on Maryland Avenue near First Street Northeast and set fire to it, according to Kathleen Arberg, a spokeswoman for the high court.

A congressional staffer, who was enjoying a lunch break on the lawn of the Capitol with friends and witnessed the fire and response, recounted hearing a series of loud bangs and saw flames licking the underside of the car, before the fire engulfed the vehicle.

“A second later, the whole thing was literally a fireball,” the staffer told CQ Roll Call. The staffer preferred not to be identified by name, but was among those who posted videos and photos of the incident on social media.

Witnesses began sharing videos on Twitter at around 1:50 p.m. Eastern time, and Hill staffers received by email an initial Capitol Police alert to avoid the area at 2 p.m.

Witnesses said that while the response from police and fire officials was swift, they were still unnerved as the car burned and explosive bangs rang out before Capitol Police and Supreme Court Police were on the scene.

“It was on fire and periodically exploding to the point where we got a little nervous,” the congressional staffer said.

The staffer thought about getting out of the area, but ended up staying nearby in case providing statements would be helpful.

Explosions continued as firefighters worked to put out the blaze. An adjacent car, also belonging to the Supreme Court Police, suffered damage too, in addition to the initial car, which was completely burned.

Supreme Court Police took witness statements from a number of people near the scene, including a woman who said she saw a man drop something through the car window and then take off running. Other witnesses said they weren’t sure if the man who ran was running because he was involved or out of fear.

“The individual suffered burns in the process. He was taken into custody by Supreme Court Police and was transported by ambulance for treatment of his injuries,” Arberg said.

The staffer recalled clearly hearing the Supreme Court Police say there was a man on the ground, badly burned, who they thought had poured gasoline on the car and set it on fire.