A D.C. firefighter’s car was vandalized Tuesday morning when fireworks were set off under it on a residential street in Northeast Washington, according to the head of the firefighters labor union and a fire department spokesman.

No injuries were reported in the incident, but the fireworks damaged the firefighter’s black Chrysler 300. The driver’s-side door panel fell off, the undercarriage and the engine were bent, and the front bumper fell off.

Police said that the case is under investigation and that a motive is not yet known. The explosion occurred shortly after 2:30 a.m. and was reported by residents who were awakened by the blast on 49th Street NE.

Officials said they do not know whether the attack was linked to the firefighter’s job with the District, a personal dispute or a neighborhood grievance, or was the work of a prankster. The car’s license plates have the fire union’s insignia.

The firefighter could not immediately be reached for comment; The Washington Post does not generally identify victims of crimes.

Edward C. Smith, the president of the D.C. union that represents firefighters, said he knows the firefighter who owns the car and was informed of the incident Tuesday morning. He said he had not yet spoken to the firefighter, who is assigned to Engine 25 on Martin Luther King Jr. Avenue in Southeast.

Smith said the firefighter helped rescue four people, including two children, from a house fire in the Barry Farm neighborhood in March. One woman died in that blaze.

Tim Wilson, a fire department spokesman, said the firefighter slept through the noise and wasn’t aware that his car had been firebombed until police knocked on his door and woke him up. “He was totally oblivious,” said Wilson, who spoke to the firefighter shortly after the incident.

Wilson said the federal Bureau of Alcohol, Tobacco, Firearms and Explosives is assisting in the investigation but has not reached any conclusions about a motive.

D.C. police spent about five hours on the scene and kept 49th Street closed between Lee Street and Sheriff Road until about 7 a.m. A police spokesman, Officer Araz Alali, said no other explosive devices were found near the car or on the street.