Arnav Gupta, of Bethesda, Md., erupted into a bright orange fireball at the Ellipse, a tourist-filled 52-acre public park that sits north of the Washington Monument, around 12:20 p.m. Wednesday.
Once the flames were extinguished, Gupta was rushed to a local hospital for treatment.
But by the evening, he had succumbed to his injuries, the US Park Police said in an early-morning statement.
Gupta had been reported missing just hours earlier on Wednesday. The Montgomery County Police Department said in a Facebook post that Gupta was last seen by family when he left his home around 9:20 a.m.
Police said they were concerned for his physical and emotional welfare