Constantino sustained burns all over his body and was semiconscious when police arrived at the scene near the Air and Space Museum, six blocks from the U.S. Capitol, WJLA-TV, Washington, reported.
Witnesses reported seeing Constantino sitting, engulfed in flames with a red gasoline canister nearby. He was transported in critical condition to a local hospital and later died of his injuries.
It remains unclear what caused him to self-immolate.
The incident was the second bizarre death near the Capitol in as many days. A Connecticut woman's car chase ended their when police shot her to death Thursday.